intro
Question 1:
What deflection angle will a string with a bob exhibit from the vertical, given the forward acceleration of the ship it's attached to, is 10 m/s²?
Topic: Physics: Motion and Forces
Correct Answer: D) 45˚
- When the ship accelerates, the bob experiences an inertial force, causing it to deflect from the vertical line.
- The angle of deflection (θ) can be calculated using the formula tanθ = ma/g, where 'm' is the mass of the bob (which gets canceled out), 'a' is the acceleration of the ship, and g is the acceleration due to gravity.
- Substituting the given acceleration (10 m/s²) for both 'a' and 'g', we find that tanθ = 1, which gives an angle θ = 45˚.
- Therefore, the correct answer is D, "45˚".
Question 2:
In a scenario where a coin is dropped in an elevator, if 't1' represents the time it takes for the coin to reach the floor when the elevator is stationary and 't2' is the time when the elevator is moving upward with constant acceleration, which of the following is true?
Topic: Physics: Motion and Forces
Correct Answer: A) t1 > t2
- In this scenario, the elevator is an accelerated frame of reference as it moves upward with constant acceleration.
- Consequently, the coin perceives an increased downward force, resulting in better overall acceleration than gravitational acceleration.
- Therefore, the time taken by the coin to reach the floor will be shorter than when the elevator is stationary, implying that 't1' is more significant than 't2'.
- Hence, the correct answer is "t1 > t2".
Question 3:
For a projectile thrown at angles (45°+q) and (45°-q), with the corresponding horizontal ranges represented by R1 and R2, respectively, what would be the value of R1/R2?
Topic: Physics: Projectile Motion
Correct Answer: A) sin²(45)
- For complementary angles of projection, the horizontal range remains the same.
- Therefore, R1/R2 equals 1.
- sin²(45) gives us a value of 1.
- Hence, the correct answer is A, "sin²(45)".
Question 4:
A stone falls from a tower and hits the ground after 6 seconds. If it's stopped 2 seconds into its fall and then rereleased, how many additional seconds will it take to reach the ground?
Topic: Physics: Motion and Forces
Correct Answer: C) 3 seconds
- The initial height of the tower can be calculated using the formula 1/2 gt² (with g representing gravitational acceleration and t the total time of fall), resulting in a height of 180m.
- The distance covered in the first 2 seconds can be calculated similarly, resulting in a distance of 20m.
- Therefore, the remaining distance to be covered is 180m minus 20m = 160m.
- If 't' represents the time taken to cover the remaining 160m starting from rest, we can use the equation 160 = 1/2 gt2 to solve for 't', which results in 3 seconds.
- Hence, the correct answer is C, "3 seconds".
Question 5:
What is the distance ratio to displacement magnitude when a body traverses a semicircle?
Topic: Physics: Motion and Forces
Correct Answer: A) π/2
- The distance covered by the body is the length of the semicircle, which is πR.
- The magnitude of displacement is the diameter of the semicircle, which is 2R.
- Therefore, the ratio of distance to displacement is πR/2R, which simplifies to π/2.
- Hence, the correct answer is A, "π/2".
Question 6:
What is the value of the ratio of displacement to distance?
Topic: Physics: Motion and Forces
Correct Answer: D) Equal or less than one
- Displacement and distance are equal for a straight path, making the ratio 1.
- For any curved path, the distance exceeds the displacement, resulting in a ratio of less than 1.
- Thus, the displacement-to-distance ratio will equal or be less than one.
- Therefore, the correct answer is D, "Equal or less than one".
Question 7:
Which of the following statements accurately describes Newton's 2nd law?
Topic: Physics - Motion and Forces
Correct Answer: B) Measures force
- Newton's 1st law, not the 2nd, defines force.
- Newton's 2nd law, on the other hand, provides a method to measure force, which is equal to mass times acceleration.
- The 2nd law does not balance force; that's the role of Newton's 3rd law.
- Therefore, the correct answer is B, "Measures force".
Question 8:
In the context of free-falling bodies of diverse masses, how would you describe their acceleration?
Topic: Physics - Motion and Forces
Correct Answer: C) Consistent across all bodies
- Acceleration due to gravity, denoted as 'g', is a constant value approximated as 9.8 m/s² in an environment close to the Earth's surface.
- Regardless of the mass or shape of the body, the acceleration of free-falling bodies remains the same, assuming no air resistance.
- Therefore, the correct answer is C, "consistent across all bodies".
Question 9:
Assuming a body's momentum and kinetic energy are equal, what is the numerical value of its velocity?
Topic: Physics: Motion and Forces
Correct Answer: C) 2 m/s
- Momentum (P) is calculated with the formula mv (mass x velocity).
- Kinetic energy (K.E.) is calculated with the formula 1/2 mv².
- If P equals K.E., then mv equals 1/2 mv².
- Solving this equation results in a velocity (v) of 2 m/s.
- Therefore, the correct answer is C, "2 m/s".
Question 10:
Two 50-meter-long trains are moving towards each other on parallel tracks at 10 m/s and 15 m/s, respectively. How long will it take for them to pass each other?
Topic: Physics - Motion and Forces
Correct Answer: B) 4s
- The total length of the two trains is 100m (50m + 50m).
- The relative velocity of the trains is 25 m/s (10 ms-1 + 15 ms-1), as they are moving in opposite directions.
- The time to pass each other is calculated by dividing the total length by the relative velocity (100 m/25 m/s).
- This gives us a time of 4 seconds.
- Therefore, the correct answer is B, "4s".
Question 11:
In which frames are Newton's laws applicable?
Topic: Physics: Motion and Forces
Correct Answer: A) Inertial frame
- Inertial (non-accelerating) motion is described by Newton's laws of motion.
- They are not fully accurate in a non-inertial (accelerating) frame of reference.
- Therefore, the correct answer is "inertial frame".
Question 12:
Two identical spheres, each with a mass of m and a speed of v, are moving towards each other and colliding elastically head-on. Which statement is accurate?
Topic: Physics: Motion and Forces
Correct Answer: B) Post-impact, the total kinetic energy is mv²
- Kinetic energy is conserved in elastic collisions.
- The spheres do not stick together; they bounce off each other.
- Therefore, the correct answer is B: "Post-impact, the total kinetic energy is mv²".
Question 13:
On smooth horizontal rails, a 1000-kg wagon is moving at 50 km/h. We drop 250 kg into it. What will be the new velocity?
Topic: Physics: Motion and Forces
Correct Answer: B) 40 km/h
- Conservation of momentum principle is used, equating initial and final momentum.
- Initial momentum is calculated with mass and initial velocity.
- Final momentum includes the new mass and the unknown new velocity.
- Solving the momentum equation yields the new velocity of 40 km/h.
Question 14:
What is the rate of change of momentum equivalent to?
Topic: Physics: Motion and Forces
Correct Answer: D) Force
- Newton's second law relates force to the change in momentum over time.
- Force is defined as the rate of change of momentum.
Question 15:
A particle travels from point A to point B in a semicircle within 1.0s. What is the magnitude of the average velocity?
Topic: Physics: Motion and Forces
Correct Answer: C) 2.0 m/s
- Displacement is the straight-line distance between the start and end points.
- Average velocity is displacement divided by time.
- The displacement in this case is the semicircle's diameter.
Question 16:
What distance is a body covering during its third second of free fall?
Topic: Physics: Motion and Forces
Correct Answer: A) 25 m
- Use the formula for distance covered in 'n' seconds during free fall: S = 10t minus 5 (where t is the time in seconds).
- For the third second, plug in t=3 to calculate the distance.
Question 17:
A missile is launched with an initial velocity of 20 m/s, aiming for maximum range. Assuming the acceleration due to gravity is 10 m/s², which of the following options correctly represents the missile range?
Topic: Physics: Motion and Forces
Correct Answer: B) 40 m
- The range of a projectile is given by R = (v²/g) * sin(2θ).
- For maximum range, the launch angle should be 45 degrees, making sin(2θ) equal to 1.
- Substituting v = 20 m/s and g = 10 m/s² gives R = 40 m.
- Therefore, the correct answer is B, "40 m".
Question 18:
A bus moving initially at speed v is halted by a retarding force F over a distance s. If the speed of the bus was increased to 3v, what amount of force would be necessary to stop it within the same distance?
Topic: Physics: Motion and Forces
Correct Answer: C) 9F
- Force required to stop is directly proportional to the square of velocity.
- Tripling the velocity increases the needed force by a factor of nine.
- Thus, the correct answer is C, "9F".
Question 19:
Select the accurate statement concerning an inelastic collision:
Topic: Physics: Motion and Forces
Correct Answer: D) Both B and C are correct
- Kinetic energy is not conserved in an inelastic collision.
- Momentum and total energy, however, are conserved in any collision.
- Therefore, the answer is D, "Both B and C are correct".
Question 20:
If a projectile is launched at two different angles, represented by (45° + q) and (45° - q), and the respective horizontal ranges are denoted as R1 and R2, which of the following options correctly represents the ratio R1/R2?
Topic: Physics: Motion and Forces
Correct Answer: A) sin²(45)
- The range of a projectile is the same for angles that add up to 90 degrees, making R1/R2 equal to 1.
- Since sin(90) is 1, this is equivalent to sin²(45), as sin(2*45) is also 1.
- Hence, the correct answer is A, "sin²(45)".
Question 21:
The displacement time graph for a particle's motion is provided below. At which point is the particle's instantaneous velocity negative?
Topic: Physics: Motion and Forces
Correct Answer: D) E
- A particle's instantaneous velocity can be determined from a displacement-time graph by looking at the slope of the tangent at any given point.
- A negative slope on a displacement-time graph indicates a negative instantaneous velocity.
- At point E, the slope decreases negatively, indicating that the instantaneous velocity of the particle is negative at this point.
- Hence, the correct answer is D or "E."
Question 22:
Given the graph below, what is the total distance traveled?
Topic: Physics: Motion and Forces
Correct Answer: A) 200 m
- The total distance an object covers can be determined from a velocity-time graph by calculating the area under the graph.
- The area represents the integral of velocity concerning time, which is displacement.
- If the graph forms a trapezium, the area can be calculated to find the total displacement or distance covered.
- Hence, the correct answer is A, "200 m."
Question 23:
An object experiences free fall under the influence of gravity. As it ascends, the acceleration is given as a = -9.8 m/s2; as it descends, the acceleration is a' = +9.8 m/s2. What is the angle between a and a'?
Topic: Physics: Motion and Forces
Correct Answer: A) 0°
- Acceleration, in the case of an object in free fall, is always directed towards the force acting on it, which is gravity.
- The force of gravity always acts downward, as does the acceleration in this scenario.
- This means accelerations a and a' are in the same direction.
- Thus, the angle between a and a' is 0°, making A the correct answer.
Question 24:
Which quantity is the largest when the highest point a projectile reaches is at its maximum?
Topic: Physics: Motion and Forces
Correct Answer: C) Time of flight
- A projectile's maximum altitude is achieved when the launch angle is 45°.
- At this angle, the range is not at its maximum.
- The flight time is the only quantity that reaches its maximum when the projectile is at this maximum height.
- Hence, the correct answer is C, "Time of flight".
Question 25:
Two bodies, one with a mass of 1 kg and the other with a mass of 4 kg, have the same kinetic energy. What is the ratio of their linear moments?
Topic: Physics: Motion and Forces
Correct Answer: C) 1:2
- With equal kinetic energy, the lighter body compensates with higher velocity for its lower mass.
- Linear momentum is given by the product of mass and velocity, \( p = mv \).
- With the same kinetic energy, the lighter body will have a smaller momentum, even though it has a higher velocity, yielding a ratio of 1:2.
- Therefore, the correct answer is C, "1:2".
Question 26:
A projectile attains the same R range when projected at two different angles. If the flight times for these angles are T1 and T2, respectively, what can be deduced about them?
Topic: Physics: Motion and Forces
Correct Answer: D) T1T2 = 2R
- The sum of the angles for the same range in projectile motion is 90 degrees.
- The relationship between the flight times for these angles is given by \( T1T2 = 2R \).
- Consequently, D, "T1T2 = 2R", is the correct answer.
Question 27:
A stone is dropped from a cliff edge. Which of the following graphs most accurately depicts the stone's falling motion?
Topic: Physics: Motion and Forces
Correct Answer: C) Graph C
- A falling stone under gravity has a constant acceleration, represented by a constant slope in Graph C.
- Thus, the correct answer is C, "Graph C".
Question 28:
What happens when the velocity of an object is doubled?
Topic: Physics: Motion and Forces
Correct Answer: C) The momentum is doubled
- Momentum is calculated by the formula \( P = mv \).
- Doubling the velocity doubles the momentum, so \( P' = m(2v) = 2P \).
- The correct answer is C, "The momentum is doubled".
Question 29:
In the context of a projectile's motion, when it hits its highest point, what is the angle between its instantaneous velocity and acceleration?
Topic: Physics: Motion and Forces
Correct Answer: B) 90°
- At the highest point, the projectile's velocity vector is horizontal while acceleration due to gravity is vertical.
- These two vectors are perpendicular at the peak of the trajectory.
- This results in an angle of 90° between them; hence, the correct answer is B, "90°".
Question 30:
At what launch angle does a projectile achieve equal range (R) and maximum height (H)?
Topic: Physics: Motion and Forces
Correct Answer: C) 76°
- For a projectile, the range is usually not equal to the maximum height except at a specific angle.
- A launch angle of approximately 76° will satisfy the condition where R equals H.
- Thus, the correct answer is C, "76°".
Question 31:
What happens to an object's momentum when its velocity is doubled, assuming the mass remains constant?
Topic: Physics: Motion and Forces
Correct Answer: C) The momentum is doubled
- A mass-velocity product determines an object's momentum.
- If the velocity of an object is doubled while its mass remains constant, the momentum will also double.
- Therefore, the correct answer is C, "The momentum is doubled".