intro
Question 1:
What is the relationship between the horizontal range and the maximum range of a projectile according to the following options?
Topic: Projectile Motion and Ranges
Correct Answer: D) R equals Rmax times sin2θ and Rmax equals R divided by sin2θ
- The relationship between the horizontal range (R) and the maximum range (Rmax) of a projectile is a fundamental concept in physics.
- It's crucial to understand that the maximum range is achieved when the angle (θ) is 45 degrees.
- The options can be assessed by substituting 45 degrees into the equations, and based on the principles of trigonometry, sin(2*45) equals 1.
- Thus, the correct answer is D, "R equals Rmax times sin2θ and Rmax equals R divided by sin2θ".
Question 2:
Considering a body falling freely under gravity (where g=10m/s²), what is the distance it falls during the time interval between the 1st and 2nd seconds of its motion?
Topic: Free Falling Bodies and Gravity
Correct Answer: A) 15 m
- To understand the motion of a freely falling body under gravity, one should consider the formula for distance fallen, which is h = ½ gt².
- The total distance fallen in the first and second seconds would be different, and the required answer is the difference between these two distances.
- By using the formula, the distance fallen in the 1st second (h1) is 5m and in the 2nd second (h2) is 20m.
- Therefore, the difference (h) is 15m, which makes option A the correct answer.
Question 3:
If a force is applied to an object, increasing its momentum from 10N's to 20N's in 1 second, what is the magnitude of the applied force?
Topic: Momentum and Force
Correct Answer: A) 10 N
- The key concept is the relationship between force, momentum and time as captured by the formula F = (Pf - Pi)/t.
- By substituting the given values into the formula, we find that the force (F) is equal to 10N.
- Hence, the correct answer is A, "10 N".
Question 4:
To what is the range of a projectile directly proportional?
Topic: Projectiles and Range
Correct Answer: C) sin²θ
- The range of a projectile is determined by the equation R = (vi² sin²θ)/g.
- From this equation, it can be inferred that the range (R) is directly proportional to sin²θ.
- Therefore, the correct answer is C, "sin²θ".
Question 5:
What is the constant rate of momentum change in a freely falling object?
Topic: Momentum and Gravity
Correct Answer: A) Equal to mg
- The rate of change of momentum for a freely falling object is determined by the product of its mass and gravitational acceleration.
- According to the physics principle of conservation of momentum, the result is equal to mg (mass x gravity).
- So, the correct answer is A, "Equal to mg".
Question 6:
A moving object possesses which of the following properties?
Topic: Properties of Moving Objects
Correct Answer: D) All of the above
- Any moving object, due to its mass and velocity, will possess momentum.
- Additionally, if it experiences a change in velocity over time, it will have acceleration.
- The object also has impulse, which is the change in its momentum over a period of time.
- Therefore, the correct answer is D, "All of the above".
Question 7:
If two objects move in opposite directions with equal velocities but different masses, what would be their relative velocity?
Topic: Relative Velocity
Correct Answer: A) Two times the original velocity
- Among bodies, relative velocity is defined as their velocity in relation to each other.
- It is calculated as the sum of their individual velocities when the bodies move in opposite directions.
- Therefore, the relative velocity in this case would be twice the original velocity.
- So, the correct answer is A, "Two times the original velocity".
Question 8:
What does the area beneath a velocity-time graph represent?
Topic: Velocity-Time Graph
Correct Answer: B) The distance travelled by the object
- The area underneath a velocity-time graph is a depiction of the integral of velocity with respect to time.
- In physics, this integral equates to the total distance covered by the object.
- Thus, the correct answer is B, "The distance travelled by the object".
Question 9:
What will be the deceleration rate of a train moving at 72 km/hr if it needs to come to a complete stop within a span of 200 meters?
Topic: Deceleration and Distance
Correct Answer: D) 1 ms-2
- To solve this problem, we first need to convert the speed from km/hr to m/s by multiplying the initial speed by 1000 and then dividing by 3600. This gives us 20 m/s.
- We can then apply the equation of motion which is 2aS = Vf² - Vi². Here, Vf is the final speed (0 in this case since the train comes to rest), Vi is the initial speed (20 m/s) and S is the stopping distance (200m).
- Solving the equation gives us a deceleration of 1 ms-2, making option D the correct answer.
Question 10:
What is the velocity acceleration at the peak of a projectile’s path?
Topic: Projectile Motion
Correct Answer: D) Equal to g
- During the projectile motion, the two-dimensional motion happens under the effect of gravity.
- Hence, regardless of the position in its path, the acceleration of a projectile is consistently equal to the gravitational acceleration (g).
- So, the correct answer is D, "Equal to g".
Question 11:
Which of the graphs accurately illustrates a hefty steel sphere descending from a 2 meter height?
Topic: Free Fall
Correct Answer: A) Graph A
- The final velocity of a freely falling body is calculated using the formula Vf = Vi + gt. In the case of free fall, the initial velocity (Vi) is zero, so Vf = gt.
- This means that the final velocity is proportional to time, which is represented by Graph A.
- Therefore, the correct answer is A, "Graph A".
Question 12:
What happens when an object moves with constant speed?
Topic: Uniform Velocity
Correct Answer: D) The displacement from the origin changes
- When an object moves with uniform speed, its speed, acceleration, and direction remain constant. The only thing that changes is its position from the initial point or origin.
- So, the correct answer is D, "The displacement from the origin changes".
Question 13:
If a constant force of 8.0N is applied for 4.0s on a 16kg object that was initially stationary, what will be the alteration in the object's speed?
Topic: Force and Speed
Correct Answer: C) 2 m/s
- By using F = ma, where F = force, m = mass, and a = acceleration, you can calculate the change in speed of an object.
- Rearranging the formula gives a = F/m. Substituting the provided values gives a = 8N/16kg = 0.5 m/s².
- The final speed can then be calculated using the formula v = at, where v is the final speed, a is the acceleration, and t is the time. Substituting the calculated acceleration and time gives v = 0.5 m/s² * 4s = 2 m/s.
- Therefore, the correct answer is C, "2 m/s".
Question 14:
A particle is uniformly accelerated from 10 km/hr to 20 km/hr with an acceleration rate of 2 km/hr². How long does this process take?
Topic: Acceleration and Time
Correct Answer: D) 5 hours
- The time taken for a uniformly accelerated particle can be calculated using the formula a = (Vf - Vi) / t, where a represents acceleration, Vf represents final velocity, and Vi represents initial velocity.
- Rearranging this formula to solve for time, we get t = (Vf - Vi) / a. Substituting the given values we get t = (20 km/hr - 10 km/hr) / 2 km/hr² = 5 hours.
- Therefore, the correct answer is D, "5 hours".
Question 15:
What does Newton's second law of motion provide a measure of?
Topic: Newton's Laws of Motion
Correct Answer: C) Force
- According to Newton's second law of motion, force is equal to mass times acceleration when applied to an object. In other words, F = ma.
- Therefore, Newton's second law of motion is used to measure force.
- Thus, the correct answer is C, "Force".
Question 16:
Assume two balls of different masses, m1 and m2, are dropped from the same height, disregarding air resistance. If the times taken for the balls to fall are t1 and t2 respectively, then which of the following holds true?
Topic: Free Fall
Correct Answer: B) t1 = t2
- In a vacuum, or when air friction is negligible, all objects fall with the same rate of acceleration, regardless of their mass. This principle is a consequence of the equivalence of inertial and gravitational mass.
- Objects falling from a certain height take the same amount of time regardless of their mass. Hence, the times t1 and t2 for the two balls should be equal.
- So, the correct answer is B, "t1 = t2".
Question 17:
A train, 150m in length, moves north at a speed of 10m/s. A bird, flying at a speed of 5m/s, moves south parallel to the train tracks. How much time will the bird require to pass the entire length of the train?
Topic: Relative Speed
Correct Answer: B) 10 seconds
- The relative speed of the bird with respect to the train will be the sum of their individual speeds since they are moving in opposite directions.
- Therefore, the relative speed (vr) is 10m/s (train) + 5m/s (bird) = 15m/s.
- The time taken (t) for the bird to cross the train can be calculated using the formula t = S/vr, where S is the length of the train.
- Substituting the values we get t = 150m / 15m/s = 10 seconds.
- Therefore, the correct answer is B, "10 seconds".
Question 18:
What is the ratio of displacement to distance?
Topic: Displacement and Distance
Correct Answer: D) Always less than or equal to 1
- An object's displacement is its overall change in position; it indicates how far out of place an object is.
- Distance is a scalar quantity.
- Since displacement can be equal to or smaller than the total length of path but never greater, the ratio of displacement to distance is always less than or equal to 1.
- Hence, the correct answer is D, "Always less than or equal to 1".
Question 19:
If a projectile is launched at 30° (R30) and 60° (R60) with the same initial velocity, which of the following is correct?
Topic: Projectiles
Correct Answer: D) R30 equals R60
- The range of a projectile launched at an angle of (θ) to the horizontal is given by the formula R = v²sin(2θ)/g, where g is the acceleration due to gravity.
- For complementary angles, like 30° and 60°, the range is the same provided the initial velocities are the same, i.e., R30 equals R60.
- Therefore, the correct answer is D, "R30 equals R60".
Question 20:
What does the inertia of an object quantifiably represent?
Topic: Inertia
Correct Answer: C) Mass
- An object's inertia refers to its resistance to change in motion.
- The greater the mass of an object, the higher its inertia, as the object resists changes in state more strongly.
- Hence, inertia is a quantitative measure of an object's mass. So, the correct answer is C, "Mass".
Question 21:
If a man is inside a car moving 36 km/hr, what is his relative speed?
Topic: Relative Speed
Correct Answer: C) Zero
- Relative speed is the speed of an object as observed from another moving object.
- As the man is inside the moving car, from the viewpoint of the car, the man is at rest.
- Thus, his speed relative to the car is zero.
- Hence, the correct answer is C, "Zero".
Question 22:
Two bodies of different masses are initially at rest on a frictionless surface. When equal forces are exerted for the same time period, which will be true for the body with a greater mass just after the forces are removed?
Topic: Force and Mass
Correct Answer: A) It has less acceleration
- According to Newton's second law, Force = mass * acceleration, or written differently, acceleration = Force / mass.
- When the same force is applied to two bodies with different masses, the body with the greater mass will have less acceleration.
- Hence, the correct answer is A, "It has less acceleration".
Question 23:
Two projectiles, named "A" and "B", are launched upwards at angles of 40 degrees and 50 degrees respectively relative to the horizontal. What would be the range of projectile "A"?
Topic: Projectiles
Correct Answer: A) Equal to the range of "B"
- The range of a projectile launched at an angle (α) with the horizontal is the same for two complementary angles.
- For example, if two projectiles are launched with the same speed but at angles (45° + α) and (45° - α) respectively, their ranges would be the same.
- So, the range of "A" will be equal to that of "B". Hence, the correct answer is A, "Equal to the range of B".
Question 24:
A motorcycle safety helmet prolongs the collision duration, hence diminishing what aspect?
Topic: Forces and Motion
Correct Answer: B) Exerted force
- The role of a motorcycle safety helmet is to extend the time of collision.
- According to the equation Force = Change in Momentum / Time, by increasing the time of collision, the force that is exerted during the collision is reduced.
- Hence, the correct answer is B, "Exerted force".
Question 25:
What is represented by the gradient of a displacement-time graph?
Topic: Motion
Correct Answer: B) Average velocity
- In a displacement-time graph, the slope or gradient represents the rate of change of displacement with respect to time.
- Mathematically, this rate of change is the velocity of the object.
- Therefore, the correct answer is B, "Average velocity".
Question 26:
At the highest point in a projectile's path, what is the acceleration?
Topic: Projectiles
Correct Answer: D) Equal to g (gravity)
- A projectile’s acceleration at the top of its trajectory is not dependent on its horizontal motion, only the vertical.
- The vertical acceleration is constant and always equal to g (gravity), irrespective of the projectile's position in its trajectory.
- Therefore, the correct answer is D, "Equal to g".
Question 27:
Which pair always shares the same direction?
Topic: Force and Motion
Correct Answer: C) Force and Acceleration
- According to Newton's second law, net forces acting on objects are always in the same direction as their accelerations.
- This is because force is a product of mass and acceleration.
- Consequently, the correct answer is C, "Force and Acceleration".
Question 28:
A body travels half of its journey at a speed of 40m/s and the other half at 50m/s. What would be its average velocity?
Topic: Velocity
Correct Answer: A) 44.4 m/s
- When an object covers equal distances at different speeds, the average velocity can be calculated using the formula, Vav = (2v1v2)/(v1+v2).
- Plugging in the values, we get: (2(40)(50))/(40+50) = 4000/90 = 44.4 m/s.
- Therefore, the average velocity is 44.4 m/s, and the correct answer is A, "44.4 m/s".
Question 29:
A ball is hurled upwards directly with a speed of 98m/s. To what altitude does the ball ascend? (Assume g = 9.8m/s2)
Topic: Kinematics
Correct Answer: C) 490 m
- The maximum height that a vertically thrown object can reach is determined by the equation H = Vi2/2g.
- If we substitute in the given values, we find that H = 98×98/2×9.8 = 490m.
- Thus, the ball will rise to a maximum height of 490 m, making the correct answer C, "490 m".
Question 30:
A ball is projected upwards at a speed of 20ms-1, making an angle of 60 degrees with the x-axis. What is the horizontal velocity of the ball at its peak?
Topic: Projectiles
Correct Answer: C) 10 ms-1
- Multiply the initial velocity by the cosine of the launch angle to find the horizontal velocity of a projectile, i.e., Vx = Vcosθ.
- Substituting the given values, we have Vx = (20) cos60 degrees = (20) (0.5) = 10ms-1.
- Therefore, the horizontal velocity of the ball at its peak is 10 ms-1, making the correct answer C, "10 ms-1".