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Physics Department
Kinematics
Questions
Statics โ Vectors, scalars & equlibrium
SUVAT Questions Horizontal motion 2 Vertical motion 3 Projectiles (Horizontal and Vertical) 7 Resolving Forces & Projectiles 15 Graphs Displacement time graphs 17 Distance time graphs 21 Exam questions 24 Olympiad problems 33 Answers 37
Equations of motion for uniform acceleration
Horizontal Motion
- A car is uniformly decelerated and brought to rest from a speed of 30 ms-^1 in 15 s. Find the acceleration.
- A car accelerates uniformly from rest at a rate of 2 ms-^2 for 6 s. It then maintains a constant speed for half a minute. The brakes are then applied and the vehicle is uniformly retarded to rest in 5 s. Find the maximum speed reached and the total distance covered. (Note acceleration changes during each part of the motion.)
- An electric train moving at 20 km per hour accelerates to a speed of 30 km per hour in 20 s. Find the acceleration and the distance travelled during the period of the acceleration. s u v a t
- A sandbag is released from a balloon which is ascending with a steady vertical speed of 8 ms-^1. If the sandbag hits the ground 15 s later, if a=+9.81 what is the initial velocity (magnitude and direction) of the sandbag relative to the ground? What was the height of the balloon when the sandbag was released?
- A cat, wishing to investigate the laws of physics, jumps out of a second floor window and falls through a height of 7 m. Calculate the velocity of the cat just before it lands and the time of fall. State any assumptions made.
SUVAT equations
Projectiles (Horizontal and Vertical Motion)
- A football is kicked from a flat roof with a horizontal velocity of 20 ms-^1. If the roof is 14 m above ground level, calculate: (a) the time taken for the football to hit the ground, (hint think vertically) b) the horizontal range of the football. (hint think horizontally; the time of flight will be the same as for vertically)
- A helicopter is hovering in mid-air when it fires its guns horizontally to strike a target on the ground. The horizontal velocity of the bullets is 200ms-1.^ If each bullet takes 4s to reach the target, find a) how far the target is horizontally from the helicopter b) how high the helicopter is at the time of firing
- An aeroplane flying horizontally with a uniform velocity of 40ms-^1 drops a bomb which hits a factory. When the bomb is released it will continue to travel horizontally at 40ms-^1 (i.e. air resistance is negligible). When the bomb is released the horizontal distance between the factory and the aeroplane is 200m. Draw a diagram Find a) The time of flight of the bomb b) how high the aeroplane is flying c) where the plane is relative to the factory when the bomb explodes (assume negligible air resistance on the plane) 40ms-^1 200m
- Harder โ a challenge An electron moving at 2.0 x 10^7 ms-^1 horizontally enters an electric field which provides a vertical force on the electron of 3.2 x 10 โ^15 N. The electron travels 4 cm horizontally through the field. Calculate: (a) the vertical acceleration of the electron, (use F = ma where F is force in Newtons and m is the mass of a moving object in kg and a is acceleration in ms-^2 ). (b) the time taken to pass through the field, (think horizontally) c) the vertical displacement of the electron on leaving the field,
- a) A ball is dropped from a height of 80 m. Calculate the time taken to reach the ground. b) A ball is thrown horizontally at 20 ms-^1 from the top of a cliff of height 80 m. It falls into the sea. For each of the following, sketch graphs (giving appropriate values on the axes) i) the horizontal component of the velocity against time. ii) the vertical component of the velocity against time. iii) the height of the ball above ground level against time
Jan 08 โ Monkey and Hunter experiment
Further Questions (answer on paper)
- The following data represents a space probe which is moving in a straight line away from Earth. Time/s 0 100 200 300 400 500 600 Velocity/ms-^1 5374 5329 5283 5238 5193 5147 (b) What does the shape of the graph tell you about the motion of the space probe? (c) Calculate, from the graph, the deceleration of the probe. (d) Calculate, from the graph, the distance travelled by the probe during the 600 s period. Note if you have a break in your y-axis, the area under the graph must go down to the real x axis i.e. where y=0. 5050 5100 5150 5200 5250 5300 5350 5400 0 100 200 300 400 500 600 700
velocity time graph
- A road test report gives the following data for a standing start acceleration test for a car. t/s 0 5 10 15 20 25 30 35 40 v/ms-^1 0 14 24 30 34 37 39 40 From the velocity/time graph above find: (a) the displacement of the car when it has reached a speed of 25 ms-^1 (b) the acceleration of the car when its speed is 30 ms-^1 0 5 10 15 20 25 30 35 40 45 0 5 10 15 20 25 30 35 40 45
velocity time graph
