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Form 3 Physics Questions and Answers on Linear Motion

In this session, several Form 3 Physics questions on linear motion will be solved. Answers are available in video format.

Lessons (31)

• 1.    (a) A body accelerates uniformly from its initial velocity, u, to the final velocity, V, in time t. the distance travelled during this time is S. If the acceleration is denoted by letter a, show that; (i) V = u + at (ii) #S = ut + 1/2 at^2# (iii)#V^2 = u^2 + 2as#(b) A body moving initially at 50m/s decelerates uniformly at #2 ms^-2# until it comes to rest.
  11m 21s

• 2.    An object dropped from a height h, attains a velocity of #6 ms^-1# just before hitting the ground. Find the value of h.
  1m 24s

• 3.    (a) A stone is thrown vertically upwards from the edges of a platform. Eventually the stone lands without bouncing, on the ground below the platform. Taking the upward velocity to be positive, sketch on the axis provided the velocity time graph of the motion of the stone. (b) A car can be brought to rest from a speed of 20 ms-1 in a time of 2s. (i) Calculate the average deceleration.
  3m 26s

• 4.    A bullet is fired horizontally at a target. Neglecting air resistance, give a reason why the horizontal acceleration of the bullet is zero.
  1m 6s

• 5.    (a) A tape attached to a moving trolley is run through ticker timer. Figure 3 shows a section of the tape after running. If the frequency of the ticker – timer is 50Hz, determine the: (i) Average velocity at intervals AB and CD. (ii) Average acceleration of the trolley. (b) A stone is released from a height, h. if the acceleration due to gravity is g, derive an expression of the velocity of the
  7m 1s

• 6.    A bullet moving at a velocity of #300ms^-1# hits a tree trunk of diameter 50cm. it emerges from the opposite side with a velocity of #150ms^-1# determine the average deceleration of the bullet in the trunk.
  2m 50s

• 7.    Figure 9 shows a speed-time graph for the journey of a motor car. Determine the distance the car travels in the first 40 seconds.
  1m 46s

• 8.    On the axes provided in Figure 11, sketch a graph of velocity (v) versus time (t) for uniformly accelerated motion given that when t=0, v is greater than zero.
  0m 31s

• 9.    (a) Figure 1 above shows the displacement time graph of the motion of a particle. State the nature of the motion of the particle between: (i) A and B (ii) B and C (iii) C and D (b) A ball is thrown horizontally from the top of a vertical tower and strike the ground at point 50m from the tower. Given that the height of the tower is 45m, determine the: (i) Time taken by the ball to hit the ground.
  5m 55s

• 10.    The graph below shows how the velocity varies with time for a body thrown vertically upwards. Determine the total distance moved by the body.
  1m 0s

• 11.    A bullet is fired horizontally from a platform 15m high. If the initial speed is #300ms^-1#, determine the maximum horizontal distance covered by the bullet.
  2m 43s

• 12.    A car starting from rest accelerates uniformly for 5 minutes to reach 30m/s. It continues at this speed for the next 20 minutes and then decelerates uniformly to come to stop in 10 minutes. On the axes provided, sketch the graph of velocity against time for the motion of the car.
  2m 59s

• 13.    The graph in Figure 6 shows the velocity of a car in the first 8 seconds as it accelerates from rest along a straight line. Use the graph to answer questions. Determine the distance travelled 3.0 seconds after the start.
  1m 27s

• 14.    Determine the acceleration of the car at 4.0 seconds from the graph given.
  3m 0s

• 15.    (a) A matatu starts from rest and accelerates to cover a distance of 49m in 7 seconds. Determine: (i) Its acceleration; (ii) Its velocity, after 7 seconds. (b) A trolley moving on a horizontal bench of height 1.2m, strikes a barrier at the edge of the bench. The brass mass on the top of the trolley flies off on impact and lands on the ground 2.5m from the edge of the bench.
  5m 8s

• 16.    In an experiment to determine the acceleration due to gravity, g, a student measured the period, T and length, L, of a simple pendulum. For a length L = 70.5cm, the period T obtained was 1.7s. Given that #T=2pi sqrt (l/g)# , determine the value of g correct to two significant figures.
  2m 20s

• 17.    Figure 7 (a) shows the acceleration-time graph for a certain motion. On the axes provided in figure 7 (b), sketch the displacement-time graph for the same motion.
  0m 36s

• 18.    (a) Figure 9 shows a velocity-time graph for the motion of a certain body. Describe the motion of the body in the region; (i) OA (ii) AB (iii) BC (b) A car moving initially at 10ms-1 decelerates at 2.5ms-1 (I) Determine: (i) Its velocity after 1.5s, (ii) The distance travelled in 1.5s, (iii) The time taken for the car to stop. (II) Sketch the velocitytime graph for the car up to the time
  9m 4s

• 19.    State the constant force that opposes the motion of a stone initially at rest, as it fails through air from a tall building.
  0m 27s

• 20.    A particle starts from rest and accelerates uniformly in a straight line. After 3 seconds it is 9m from the starting point. Determine the acceleration of the particle.
  1m 35s

• 21.    Figure 3 shows a graph of velocity against time for a moving body. Describe the motion of the body during the 10 seconds.
  1m 27s

• 22.    A ball of mass 200g is thrown vertically upwards with velocity of #5ms^-1#. The air resistance is 0.4 N. Determine: (i) The net force on the ball as it moves up; (Take acceleration due to gravity g = #10ms^-2#) (ii) The acceleration of the ball (iii) The maximum height reached by the ball.
  3m 49s

• 23.    A stone thrown vertically upwards reaches a height of 100m. Determine the: (i) Initial velocity of the stone. (Neglect air resistance and take g = #10ms^-2#) (ii) Total time the stone is in air.
  4m 58s

• 24.    Figure 9 shows graph of velocity against time for a ball bearing released at the surface of viscous liquid. Explain the motion of the ball bearing for parts; (i) OA (ii) AB
  4m 28s

• 25.    Figure 2 shows a section of a curved surface ABCD. Point A is higher than point B while BCD is horizontal. Part ABC is smooth while CD is rough. A mass m is released from rest at A and moves towards D. State the changes in the velocity of m between; (a) B and C (b) C and D
  1m 31s

• 26.    Figure 9 shows a velocity-time graph for the motion of a body of mass 2kg. (a) Use the graph to determine the: (i) Displacement of the body after 8 seconds. (ii) Acceleration after point B (iii) Force acting on the body in part (a) (ii). (b) Sketch a displacement-time graph for the motion from point A to C.
  4m 35s

• 27.    (a) Figure 7 (drawn to scale) shows a section of tape after passing through a ticker timer operated at a frequency of 50 Hz. The tape is attached to a trolley moving in the direction shown. (i) Determine the velocity between: (I) P and Q (II) X and Y (ii) Determine the acceleration of the trolley. (b) Two bodies of masses 5kg and 8kg moving in the same direction with velocities #20ms^-1# and
  6m 4s

• 28.    Figure 12 shows the path of a light ball projected horizontally. The ball is then made to spin in an anticlockwise direction as it moves: (i) On the same axis, sketch the new path of the ball. (ii) Explain how the ball attains the new path.
  2m 28s

• 29.    (a) A tape attached to an accelerating trolley passes through a ticker timer that makes dots on it at a frequency of 50Hz. The ticker timer makes 10 dots on a 10 cm long tape such that; the distance a between the first two dots is 0.5cm and the distance b between the last two dots is 1.5cm. (i) Determine the velocity of the trolley at: (I) Distance a (II) Distance b (ii) Determine the
  3m 55s

• 30.    On the axis provided, sketch a displacement-time graph for a trolley moving down frictionless inclined plane till it reaches the end of the incline.
  0m 41s

• 31.    A student throws a tennis ball vertically upwards from the ground and it lands back after 8 seconds. (Acceleration due to gravity g=#10ms^-2#). Determine the: (i) Maximum height reached by the ball (ii) Velocity with which the ball hits the ground.
  3m 9s