CBSE 9th Physics | Motion NCERT Problems with Solutions- Part 2

Motion NCERT Problems with Solutions- Part 2

Motion is a very important topic of Physics. Here are Motion NCERT Problems with Solutions for your practice

Problem 1. A motorboat starting from rest on a lake accelerates in a straight line at a constant rate of 3.0 m s-2 for 8.0 s . How far does the boat travel during this time?

Answer.

image

Problem 2. Fig. shows the distance-time graph of three objects A, B and C. Study the graph and answer the following questions:

clip_image016

Which of the three is traveling the fastest?

Are all three ever at the same point on the road?

How far has C traveled when B passes A?

How far has B traveled by the time it passes C?

 

image

(ii) No, all three do not meet at any point on the road,

(iii) When B passes A at point N (at 1.2 hours), C is at a distance of approximately 8 km from

the origin O.

(iv) B passes C at 0.7 hours. During this time B covers distance of 6 km.

Problem 3. A ball is gently dropped from a height of 20 m. If its velocity increases uniformly at the rate of 10 ms-2, with what velocity will it strike the ground? After what time will it strike the ground?

Answer.

image

Problem 4. The speed-time graph for a car is shown is Fig.

clip_image036

(a) Find how far does the car travel in the first 4 seconds. Shade the area on the graph that represents the distance traveled by the car during the period.

(b) Which part of the graph represents uniform motion of the car?

 

Answer.

(a) On horizontal axis, 5 small divisions = 2 s On vertical axis, 3 small divisions = 2 m/s

clip_image030[1] Area of 15 small squares

= 2 s x 2 m/s = 4m

Area of 1 small square =4/15m

Total area under the speed-time graph from time 0 to 4 s

= 57 small squares + 1/2 x 6 small squares

= 60 small square

Distance traveled by the car in first 4 seconds

= Area under the speed-time graph from 0 to 4 s

= 60 small squares

= 60 x 4/15 m

= 16 meter.

 

(b) After 6 s, the car has a uniform motion for straight part of graph BC.

 

Problem 5. State which of the following situations are possible and give an example for each of these:

(a) an object with a constant acceleration but with zero velocity.

(b) an object moving in a certain direction with an acceleration in the perpendicular direction.

 

Answer.

(a) Yes, a body can have acceleration even if its velocity is zero. When a body is thrown

up, at highest point its velocity is zero but it has acceleration equal to acceleration due to gravity.

(b) Yes, when an object moves on a circular path, it has centripetal acceleration which is perpendicular to displacement.

Problem 6. An artificial satellite is moving in a circular orbit of radius 42250 km. Calculate its speed if it takes 24 hours to revolve around the earth.

Answer.

image

Share

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

*