A block of mass 2 kg rests on a rough inclined plane making an angle of 30° with the horizontal. The coefficient of static friction between the block and the plane is 0.7. The frictional force on the block is
9.8 N
0.7 x 9.8 x √3 N
9.8 x √3 N
0.7 x 9.8 N
A man slides down a light rope whose breaking strength is η times his weight .What should be his maximum acceleration so that the rope does not break ?
g (1 - η)
ηg
g /1+η
g/1 - η
When two surfaces are coated with lubricant,then they
stick to each other
slide upon each other
roll upon each other
none of these
A cricket player catches a ball of mass 100 g and moving with a velocity of 25 ms-1. If the ball is caught in 0.1s, the force of the blow exerted on the hand of the player is
4 N
25 N
40 N
250 N
If the force on a rocket moving with a velocity of 300 m/s is 345 N, then the rate of combustion of the fuel ,is
0.55 kg/s
0.75 kg/s
1.15 kg/s
2.25 kg/s
Physical independence of force is a consequence of
third law of motion
second law of motion
first law of motion
All of the above
A balloon contains 10 g of air. The air begins to escape from a small hole in the balloon at the rate of 4 cms-1 and it completely shrinks in 2 seconds. What is the average force on the balloon?
5 dyne
10 dyne
15 dyne
20 dyne
Two balls of mass 1 kg and 2 kg respectively are connected to the two ends of the spring. The two balls are pressed together and placed on a smooth table. When released the lighter ball moves with acceleration of 2 ms-2. The acceleration of the heavier ball will be
4 ms-2
2 ms-2
1 ms-2
0.5 ms-2
An army vehicle of mass 1000 kg is moving with a velocity of 10 m/s and is acted upon by a forward force of 1000 N due to engine and a retarding force of 500 N due to friction.What will be its velocity after 10 sec ?
5 m/s
10 m/s
15 m/s
20 m/s
A force of 100 N need to be applied parallel to a smooth inclined plane just to hold a body on it. The angle of inclination of the inclined plane is 300. How much horizontal force need to be applied to do the same?
50 N
87 N
100 N
115 N
