Motion Worksheet-18

Motion Worksheet-18

61. What can you say about the motion of a body if its speed-time graph is a straight line parallel to the time axis?

62. What conclusion can you draw about the speed of a body from the following distance-time graph?

63. What can you say about the motion of a body whose distance-time graph is a straight line parallel to the time axis?

64. What conclusion can you draw about the acceleration of a body from the speed-time graph shown below?

65. A satellite goes round the earth in a circular orbit with constant speed. Is the motion uniform or accelerated? 

66. What type of motion is represented by the tip of the 'seconds' hand' of a watch? Is it uniform or accelerated?

67. If a body moves with uniform velocity, its acceleration is....................

68. The slope of a distance-time graph indicates...............of a moving body.

69. The slope of a speed-time graph of a moving body gives its..................

70. In a speed-time graph, the area enclosed by the speed-time curve and the time axis gives the.............by the body.

71. It is possible for something to accelerate but not change its speed if it moves in a……………

72.  Is the uniform circular motion accelerated? Give reasons for your answer.

73. Write the formula to calculate the speed of a body moving along a circular path. Give the meaning of each symbol which occurs in it.

74. Explain why, the motion of a body which is moving with constant speed in a circular path is said to be accelerated.

75. What is the difference between uniform linear motion and uniform circular motion? Explain with examples.

76. State an important characteristic of uniform circular motion. Name the force which brings about uniform circular motion.

77. Find the initial velocity of a car which is stopped in 10 seconds by applying brakes. The retardation due to brakes is 2.5 m/s².

78. Describe the motion of a body which is accelerating at a constant rate of 10 m/s^–2. If the body starts from rest, how much distance will it cover in 2 s?

79. A motorcycle moving with a speed of 5 m/s is subjected to an acceleration of 0.2 m/s². Calculate the speed of the motorcycle after 10 seconds, and the distance travelled in this time.

80. A bus running at a speed of 18 km/h is stopped in 2.5 seconds by applying brakes. Calculate the retardation produced.

Answer:

61. The speed of body is constant (or uniform)

62. Uniform speed

63. The body is not moving. It is stationary

64. Non-uniform acceleration

65. Accelerated

66. Uniform circular motion ; Accelerated

67. Zero

68. Speed

69. Acceleration

70. Distance travelled

71. Circular path

72. –

73. –

74. –

75. –

76. –

77. 25 m/s

V = u + at where a = -2.5 m/s² and t =10 and v = 0 since the car is stopped.

78. Use equation of motion

S = ut + ½ at²

S = 0t + ½  10 × 2 × 2

S = 20 m

79. –

80. Using equation of motion;

V = u + at, putting the values of u,v and t

U = 5 m/s ( converting into m/s) , t = 2.5 sec and v = 0

a = -2 m/s²