Advertisements
Advertisements
Question
A speeding car changes its velocity from 108 kmh−1 to 36 kmh−1 in 4 s. Calculate its deceleration in
- ms−2
- kmh−2.
Advertisements
Solution
Initial velocity = u = 108 kmh−1
u = `108xx5/18` m−1
u = 30 ms−1
Final velocity = v = 36 kmh−1
v = `36xx5/18` ms−1
v = 10 ms−1
Time = t = 4 S
Deceleration = a = `("v"-"u")/"t"`
a = `(10-30)/4`
a = `-20/4` = −5 ms−2
a = `(-5xx3600xx3600)/1000` kmh−2 = −64800 kmh−2
APPEARS IN
RELATED QUESTIONS
What is the Differnece between speed and velocity ?
Bus X travels a distance of 360 km in 5 hours whereas bus Y travels a distance of 476 km in 7 hours. Which
bus travels faster ?
Arrange the following speed in increasing order (keeping the least speed first):
A bicycle moving with a speed of 200 m/min.
A tortoise moves a distance of 100 metres in 15 minutes. What is the average speed of tortoise in km/h ?
Write the formula to calculate the speed of a body moving along a circular path. Give the meaning of each symbol which occurs in it.
A train takes 2 h to reach station B from station A, and then 3 h to return from station B to station A. The distance between the two stations is 200 km. Find:
The average speed,
The average velocity of the train.
A car is moving in a straight line with speed 18 km h-1. It is stopped in 5 s by applying the brakes. Find:
- the speed of car in m s-1
- the retardation and
- the speed of car after 2 s of applying the brakes.
A train travels with a speed of 60 km h-1 from station A to station B and then comes back with a speed 80 km h-1 from station B to station A. Find -
- The average speed
- The average velocity of the train.
What are the uses of equations of motion?
Distinguish between speed and velocity.
