Question

1. (a) Convert a speed of 54 km/hr into m/s.
(b) Change the speed of 6 m/s into km/hr.
(c) A driver decreases the speed of a car from 25 m/s to 10 m/s in 5 seconds. Find the acceleration of car.

Answer 1

Answer:

1. 1 kilometer is equal to 1000 meters.
2. 1 Hour is equal to 60 minutes.
3. 1 minute is equal to 60 seconds.
4. Hence 1 hour is equal to 60*60 =36000 seconds
5. To convert 54 km/h into m/s
6. = 54 * 1000 /60 *60
7. =54000/3600 =540/36
8. =15 m/s
9. Hence, 54 km/h is equal to 15 m/s.

Explanation:

FROM THE SUM YOU GET THE IDEA OF CONVERISON

2)6 m/sec = (6 x 18) / 5 =21.6 km/hr

3)V = u + at .

U is initial velocity, V final velocity in time t sec and a is the acceleration.

Here,

v = 10m/sec and u = 25 m/sec t = 5 sec.

∴ 10 = 25 + 5a ⇒ a = (10–25)/5

= -15/5 = -3 m/sec/sec.

Answer 2

Answer:

change the speed of 5m/s into km/hr