Class Notes NCERT Solutions for CBSE Students
Question: With the help of graph, show the uniform acceleration and uniform retardation of a body.
Answer:
OA – shows uniform acceleration.
CB – shows uniform retardation.
Question: What conclusion do you draw about acceleration of the particle in motion from given velocity-time graph?
Answer: (a) No acceleration, (b) Uniform acceleration
Question: A car accelerates uniformly from 20 km/h to 35 km/h in 5 s. Calculate (i) the acceleration and (ii) the distance covered by the car in that time.
Answer:
Question: The odometer of a car reads 1800 km at the start of a trip and 2400 km at the end of the trip. If the trip took 10 h. Calculate the average speed of the car in km/h and m/s.
Answer: Distance covered by the car
s = 2400 – 1800 = 600 km.
Trip time = 10 hr
Average speed = ?
(i) Vav = 600 km.
(ii) In m/s (60 km/h) = 60 × 1000/60 × 60 = 16.6 m/s.
The average speed of the car in km/h = 60 km/h and in m/s is 16.6 m/s.
Question: An object travels 16 m in 4 s and then another 16 m in 3 s. What is the average speed of the object?
Answer: Total distance traveled by the object = 16 m + 16 m
= 32 m
Total time taken = 4 s + 3 s = 7
∴ Average speed = Total distance traveled/Total time taken
= 32/7 = 4.57 m/s.
∴ The average speed of the object is 4.57 m/s.
