CBSE
Multiple Choice QuestionsA car covers 2/5 of a certain distance with speed v1 and rest 3/5 part with velocity v2. The average speed of the car is :
If a body loses half of its velocity on penetrating 3 cm in a wooden block then how much will it penetrate more before coming to rest?
1 cm
2 cm
3 cm
4 cm
Apparent frequency of sound of engine is changing in the ratio 5/3 under the condition that engine is first aprroaching and then receding away from the observer. If velocity of sound is 340 m/s, then velocity of engine is
340 m/s
170 m/s
85 m/s
310 m/s
The ratio of the numerical value of the average velocity and average speed of body is always
unity
unity or less
unity or more
less than unity
A wheel of car is revolving at the rate of 1200 cycle/min. On pressing the accelerator, after 10s, it does 4500 cycle/min then radial acceleration of the wheel is
30 rad/s2
1880 degree/s2
40 rad/s2
1980 degree/s2
If a body travels half the distance with velocity v1 and the next half with velocity v2,its average velocity will be given by
A police jeep is chasing with a velocity of 45 km/h, a thief in another jeep moving with velocity 153 km/h. Police fire a bullet with muzzle velocity of 180 m/s. The velocity with which it will strike the car of the thief is :
150 m/s
27 m/s
450 m/s
250 m/s
A stone is dropped in 19.6 m depth well, echo is heard in 2.06 s, then velocity of sound is
315.2 m/s
320.5 m/s
326.7 m/s
332.4 m/s
A coin is dropped in a lift. It takes time t1 to reach the floor when the lift is stationary. It takes times t2 when the lift is moving up with constant acceleration. Then:
t1 > t2
t2 > t1
t1 = t2
t1 >> t2
An observer is coming towards plane mirror with a speed of 6 m/s, then apparent velocity of his image is
6 m/s
4 m/s
12 m/s
3 m/s
