Class 9 Motion Important QuestionsImportant Questions Notes NCERT Solutions
Motion Important Questions
- Define uniform circular motion and give example of it. Why is it called accelerated motion?
- A car moves with a speed of 30 km/h for half an hour, 25 km/h for one hour and 40 km/h for two hours. Calculate the average speed of the car.
- Derive the equation for position – time relation by graphical method.
- A ball is gently dropped from a height of 20 m. If its velocity increases uniformly at the rate of 10 m s-2, with what velocity will it strike the ground? After what time will it strike the ground?
- A train starts its journey from station P; accelerates at the rate of 2 m s-2, and reaches its maximum speed in 10 s. It maintains this speed for 30 min and retards uniformly to rest at the station Q after the next 20 s. Calculate:
- the maximum speed of the train.
- the distance between stations P and Q.
- A boy runs for 20 min at a uniform speed of 18 km/h. At what speed should he run for the next 40 min so that his average speed becomes 24 km/h?
- A train accelerated from 10 km/h to 40 km/h in 2 minutes. How much distance does it cover in this period? Assume that the tracks are straight.
- A train starts from rest and accelerates uniformly at the rate of 5 m s-2 for 5 sec. Calculate the velocity of train in 5 sec.
- A bullet leaves a rifle with a muzzle velocity of 1042 m/s. While accelerating through the barrel of the rifle, the bullet moves a distance of 1.680 m. Determine the acceleration of the bullet (assume a uniform acceleration).
- A bike riding at 22.4 m/s skids to come to a halt in 2.55 s. Find the skidding distance of the bike.
- A race of scooter is seen accelerating uniformly from 18.5 m/s to 46.1 m/s in 2.47 sec. Determine the acceleration of the scooter and the distance traveled.
- A car is travelling with a speed of 36 km/h. The driver applied the brakes & retards the car uniformly. The car is stopped in 5 sec. Find (i) The acceleration of car & (ii) Distance before it stops after apply breaks?
- Robbers in a car travelling at 20 m/s pass a policeman on a motorcycle at rest. The policeman immediately starts chasing the robbers. The police man accelerates at 3 m/s² for 12 s and thereafter travels at a constant velocity. Calculate the distance covered by the policeman before he overtakes the car.
- The variation of the velocity of a particle moving along a straight line is illustrated in the graph given below. Find the distance covered by the particle in 4 seconds.