Advertisements
Advertisements
Question
When a car driver travelling at a speed of 10 m/s applies brakes and brings the car to rest in 20 s, then retardation will be :
Options
+ 2 m/s2
− 2 m/s2
− 0.5 m/s2
+ 0.5 m/s2
Advertisements
Solution
+ 0.5 m/s2
The term “retardation” means negative acceleration.
Initial velocity = 10 m/s
Final velocity = 0 m/s
Time taken = 20 s
Acceleration = `"0-10"/20`
⇒ Acceleration = `-0.5 "m/s"^2`
⇒ Retardation = 0.5 `"m/s"^2`
APPEARS IN
RELATED QUESTIONS
A train starting from a railway station and moving with uniform acceleration attains a speed 40 km h−1 in 10 minutes. Find its acceleration.
Fill in the following blank with a suitable word:
Acceleration is the rate of change of ______ It is measured in ______
Name the quantity which is measured by the area occupied under the velocity-time graph.
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.
If a stone and a pencil are dropped simultaneously in vacuum from the top of a tower, then which of the two will reach the ground first? Give reason.
A car starting from rest acquires a velocity 180m s-1 in 0.05 h. Find the acceleration.
State how the velocity-time graph can be used to find
The acceleration of a body
Can you suggest a real-life example about the motion of a body from the following velocity – time graph?
The velocity-time graph (Fig. 8.5) shows the motion of a cyclist. Find (i) its acceleration (ii) its velocity and (iii) the distance covered by the cyclist in 15 seconds.
Draw a velocity versus time graph of a stone thrown vertically upwards and then coming downwards after attaining the maximum height.
