PROJECTILE MOTION ACCELERATION DUE TO GRAVITY 2021

ACCELERATION DUE TO GRAVITY : PROJECTILE MOTION 24. An object is free falling towards the surface of the Earth. Which ONE of the following best describes the direction of acceleration of the object? A. The acceleration is 9,8 m-s-2 downward. B. The acceleration is 9,8 m-s-2 upward. C. The acceleration is less than 9,8 m-s-2 downward. D. The acceleration is less than 9,8 m-s-2 upward. 17. Aball is thrown vertically upwards. Which ONE of the following quantities will be zero when it reaches maximum height? A. acceleration C. gravitational potential energy 9. An object is thrown vertically upwards. Which ONE of the following regarding the object's velocity and acceleration at the highest point of its motion is B. kinetic energy D. gravitational force CORRECT? Ignore the effects of friction. 8. Aball is thrown vertically upwards. Which ONE of the following physical quantities has a non-zero value at the instant the ball changes direction? A. Acceleration C. Momentum VELOCITY ACCELERATION A Zero Zero B Zero Upwards C Maximum Zero D Zero Downwards B. Kinetic energy D. Velocity 5. An object is thrown vertically upwards from the ground. Which ONE of the following is CORRECT regarding the direction of the (2) (2) (2) acceleration of the object as it moves upwards and then downwards? Ignore the effects of air friction? OBJECT MOVING OBJECT MOVING UPWARDS DOWNWARDS A Downwards Upwards B Upwards Downwards C Downwards Downwards D Upwards Upwards (2)

3. Astone is projected vertically upwards from the top of a building at a speed of v m-s~1. The position-time graph below represents the motion of the stone. Ignore the effects of air resistance. o y(m) e - Which ONE of the combinations below regarding the magnitudes of the stone's velocity and acceleration, at time t1, is CORRECT? MAGNITUDE OF MAGNITUDE OF VELOCITY ACCELERATION (m.s'1) (m.s'Z) A 0 9,8 B 0 0 C Vv 0 D Vv 9,8 (2) 28. The velocity-time graph below represents the vertical motion of an object. A . Tirr;e (s) Velocity (m-sT) X Which ONE of the following corrc'actly describes the displacement Ay and acceleration of the object at point indicated on the graph? Displacement | Acceleration A Zero -9,8 B Ay zero C Ay 9,8 D -Ay 9,8 (2)

-V \/ What is the displacement of the body in m, in time 2t? A. 5t B. 2vt C. vt D. zero 41. Ahot air balloon is rising vertically at a constant speed of 5 m-s-1 when the camera of one of its occupants falls overboard. The camera will A. initially hang at rest and then fall downwards. B. immediately start falling downwards at a constant acceleration of 9,8 m-s-2. C. continue moving upwards at a constant speed of 5 m-s-1. D. initially rises at 5 m-s-1, after which its speed will decrease to 0 m-s-1 and then it starts to fall. 42. Which one of the following statements is false for an object starting from rest and experiencing free fall? (Ignore friction) A. Velocity is proportional to the time for which the object falls. B. Displacement is proportional to the acceleration due to gravity. C. Displacement is proportional to the square of the time taken. D. Displacement is proportional to the square of the final velocity. 45. A boy standing on a bridge, throws a stone vertically downward as hard as he can. Which statement concerning the acceleration of the stone after it has left his hand, is TRUE? Ignore any effects of air friction. A. Its acceleration is equal to "g". B. Its acceleration is greater than "g". C. Its acceleration is less than "g". D. Its acceleration is at first greater than "g" then it becomes equal to "g". QUESTION 4 A velocity-time graph below shows the motion of a projectile. Study the graph and answer the following questions. (2)

-49 4.1 What is the physical quantity given by the gradient of the graph? (1) QUESTION 5 The velocity-time graph below indicates the motion of the ball that is thrown upwards from a balcony of a building. It takes 0,5 s for the ball to reach it's highest point above the balcony, after which it falls past the 05 balcony and hits the ground. / Ignore the effects of friction. velocity (m-s-1) A © . - 5.1 State the numerical value of: 5.1.1 The gradient of the velocity-time graph. Give a reason for your answer. (2) QUESTION 3 (Start on a new page.) A ball, of mass 0,06 kg, is thrown vertically upwards from the balcony of a building, 3 m above the ground. The ball reaches a maximum height h above the ground, as shown in the diagram below. Ignore the effects of air resistance.

velocity (m-s-1) © [e") -19,6 -30,18 Y 7.1 What is the acceleration of the ball at time 1,02 s? (2) 7.2 Calculate the displacement of the ball. (2) QUESTION 9 The position-time graph for a tennis ball thrown vertically upwards from the second floor of a school building is shown below. Ignore all effects of air friction. o Position (m) 4, | | | ’ | ! | ! 1 1 1 1 1 1 1 1 | | t1 t2 Time (s) The height of the second floor is 6.5 m. The ball rises 0.9 m from the point of projection before it starts to fall to the ground 9.1 Write down the magnitude and direction of the acceleration of the ball while it is moving upwards. (2) QUESTION 19 A ball is projected vertically upwards from the ground next to a building. The ball reaches a maximum height above the ground before moving downwards. On its way down it passes a window 2,2 m tall in the building in 0,2 s. The bottom of the window is 1,2 m above the ground Ignore the effects of air friction. 19.1 Write down the acceleration of the ball at the maximum T 2 height. 19.2 Write down the magnitude of the velocity of the ball at the maximum height. 19.3 Calculate the velocity of the ball at the top of the 1, window. D I ] s e e N\ plt— 3 _— — Ce— — (4)