CBSE
A boy of mass 40 kg is climbing a vertical pole at a constant speed. If the coefficient of friction between his palms and the pole is 0.8 and g = 10 m/s2, the horizontal force that he is applying on the pole is
300 N
400 N
500 N
600 N
If the earth were to suddenly contract to of its present radius without any change in its mass, the duration of the new day will be nearly
24/n h
24 n h
24/n2 h
24 n2 h
A player caught a cricket ball of mass 150 g moving at the rate of 20 ms-1 . If the catching process be completed in 0.1 s, the force of the blow exerted by the ball on the hands of the player is
0.3 N
30 N
300 N
3000 N
A uniform metal chain is placed on a rough table such that one end of it hangs down over the edge of the table. When one-third of its length hangs over the edge, the chain starts sliding. Then, the coefficient of static friction is
Two masses M and M/2 are joined together by means of light inextensible string passed over a frictionless pulley as shown in the figure. When the bigger mass is released, the small one will ascend with an acceleration of
g
An athlete throws a discus from rest to a final angular velocity of 15 rad/s in 0.270 s before releasing it. During acceleration, discus moves a circular arc of radius 0.810 m. Acceleration of discus before it is released is
45
182
187
192
A cyclist is moving in a circular track of radius 80 m with a velocity v = 36 km/h. He has to lean from the vertical approximately through an angle (Take g = 10 ms-2)
From the top of tower, a stone is thrown up. It reaches the ground in t1 second. A second stone thrown down with the same speed reaches theground in t2 second. A third stone released from rest reaches the ground in t3 second. Then
A cricket ball of mass 0.25 kg with speed 10 m/s collides with a bat and returns with same speed within 0.01 s. The force acted on bat is
25 N
50 N
250 N
500 N
An ice cart of mass 60 kg rests on a horizontal snow patch with coefficient of static friction . Assuming that there is no vertical acceleration, find the magnitude of the maximum horizontal force required to move the ice cart. (g= 9.8 ms-2)
100 N
110 N
209 N
196 N