Question

V. Numerical Problems
30. A velocity of 20 km/h is represented by an arrow of length 5 cm. What velocity is represented
by an arrow of length 7.5 cm?
(Ans. 30 km/h)
31. An object is moving with a velocity of 5 m/s in a particular direction. Calculate the distance
travelled by it in 5 seconds.
(Ans. 25 m)
32. A body is thrown up with a velocity of 20 m/s. It retards uniformly at the rate of 10 m/s2
Find the velocity of the body after 2 seconds.
(Ans. Zero]
33. A body is moving at a constant speed of 10 km/h. Draw its speed-time graph. Calculate the distance
travelled by the body during the time interval 10 min to 30 min, using the speed-time graph. (Ans. 3.33 km]
34. The minute hand of a clock is 7 cm long. Find the displacement and distance covered by it
from 9:00 a.m. to 9:30 a.m.
[Ans. 14 cm, 22 cm)
35. A stone is thrown vertically upwards with a velocity of 40 m/s and is caught back.
Taking g = 10 m/s2, calculate the maximum height reached by the stone. What is the net displacement and total
distance covered by the stone?
(Ans. 80 m, net displacement = 0, total distance = 160 m)​

Answer 1

Answer:

30. Velocity shown by arrow of 5 cm= 20 km/h

Velocity shown by arrow of 1 cm= 4 km/h

Velocity shown by arrow of 7.5 cm= 4*7.5= 30 km/h

31. Distance = speed * time = 5 * 5 = 25 m

32. Given:

u=20 m/s

a=-10 m/s^2

t=2 s

v=u+at=20+(-10)*2=20-20=0