# NCERT Class 9 Physics Numerical Questions for Motion Board Sample Problems

Get unlimited access to the best preparation resource for CBSE : fully solved questions with step-by-step explanation- practice your way to success.

Question 1. A train accelerates from 36 km/h to 541 km/h in 10 sec.

(j) Acceleration

(ii) The distance travelled by car.

Answer

a) Acceleration is given by

So

b) Distance is given by

S

So s=125m

Question 2. A body whose speed is constant

(a) Must be accelerated

(b) Might be accelerated

(c) Has a constant velocity

(d) Cannot be accelerated.

Answer

Might be accelerated

Question 3. A truck traveling at 54 km/h is slow down to 36 km/h in 10 sec. Find the retardation of

Answer

Acceleration is given by

So a=-.5 m/

Negative sign implies retardation

Question 4. A particle is moving in a circle of diameter 20m. What is its distance and as per the table given below

S.No | Rounds | Displacement | Distance |

1 | 1 | ||

2 | 1.5 | ||

3 | 2 | ||

4 | 2.5 |

Answer:

S.No | Rounds | Displacement | Distance |

1 | 1 | 0 | |

2 | 1.5 | 20m | |

3 | 2 | 0 | |

4 | 2.5 | 20m |

Question 5. A scooter travelling at 10 m/s speed up to 20 m/s in 4 sec. Find the acceleration of train.

Answer

Acceleration is given by

So a=1.25 m/

Question 6. A train starts from rest and accelerate uniformly at the rate of 5 m/sā for 5 sec.

Calculate the velocity of train in 5 sec.

Answer

25m/s

Question 7. A object moves with uniform positive acceleration. Its velocity-time graph will be

(a) A straight line parallel to the time axis

(b) A straight line inclined at an obtuse angle to the time axis

(c) A straight line inclined at an acute angle to the time axis

(d) None of these.

Solutions (c)

Question 8. The maximum speed of a train is 90 km/h. It takes 10 hours to cover a distance of 500 km.

Find the ratio of its average speed to maximum speed?

Solution

Average speed km/hr

Ratio of average speed to maximum speed= 50:90=5:9

Question 9. A car start from rest and acquire a velocity of 54 km/h in 2 sec. Find (i) the acceleration (ii) distance travelled by car assume motion of car is uniform?

Solution

a) Acceleration is given by

So a=7.5 m/

b) Distance is given by

Question 10. An object dropped from a cliff falls with a constant acceleration of 10 m/. Find its speed 5 s after it was dropped.

Solution:

m/s

Question 11. A ball is thrown upwards and it goes to the height loo m and comes down

1) What is the net displacement?

2) What is the net distance?

Solution:

As it comes down to the initial point

Net displacement is zero

Net distance=200 m

**Practice Questions**

Question 12. two cars A and B race each other. The Car A ran tar 2 min at a speed of 7.5 km/h, slept for

56 min and again ran for 2 min at a speed of 7.5 km/h. find the average speed of the car A in the race.

Question 13. Anand leaves his house at 8.30 a.m. for his school. The school is 2 km away and classes start at 9.00 a.m. If he walks at a speed of 3 km/h for the first kilometer, at what speed should he walk the second kilometer to reach just in time?

Question 14. An object moves along a straight line with an acceleration of 2 m/. If its initial speed is 10 m/s, what will be its speed 2 s later?

Question 15. A bullet hits a Sand box with a velocity of 20 m/s and penetrates it up to a distance of 6 cm.

Find the deceleration of the bullet in the sand box.

Question 16. A particle experiences constant acceleration for 20 seconds after starting from rest. If it travels a distance in the first 10 seconds and distance in the next 10 seconds then,

(a)

(b)

(c)

(d)