In the figure given below, the position-time graph of a particle of mass 0.1 Kg is shown. The impulse at t = 2 sec is 

(1) 0.2 kg m sec^–1

(2) –0.2 kg m sec^–1

(3) 0.1 kg m sec^–1

(4) –0.4 kg m sec^–1

The tension in the string revolving in a vertical circle with a mass m at the end which is at the lowest position 

(1) $\frac{m{v}^2}{r}$

(2) $\frac{m{v}^2}{r}-mg$

(3) $\frac{m{v}^2}{r}+mg$

(4) mg

When two surfaces are coated with a lubricant, then they 

(1) Stick to each other

(2) Slide upon each other

(3) Roll upon each other

(4) None of these

A man is standing at a spring platform. Reading of spring balance is 60 kg-wt. If a man jumps outside the platform, then reading of spring balance:

(1) first increases then decrease to zero.

(2) decreases.

(3) increases.

(4) remains same.

A body, whose momentum is constant, must have a constant: 

(1) force.

(2) velocity.

(3) acceleration.

(4) All of these

If a cyclist moving with a speed of 4.9 m/s on a level road can take a sharp circular turn of radius 4 m, then coefficient of friction between the cycle tyres and road is 

(1) 0.41

(2) 0.51

(3) 0.61

(4) 0.71

A body of mass 5 kg is moving in a circle of radius 1m with an angular velocity of 2 radian/sec. The centripetal force is 

(1) 10 N

(2) 20 N

(3) 30 N

(4) 40 N

If a person with a spring balance and a body hanging from it goes up and up in an aeroplane, then the reading of the weight of the body as indicated by the spring balance will 

(1) Go on increasing

(2) Go on decreasing

(3) First increase and then decrease

(4) Remain the same

Rocket engines lift a rocket from the earth surface because hot gases with high velocity:

(1) push against the earth.

(2) push against the air.

(3) react against the rocket and push it up.

(4) heat up the air which lifts the rocket.

A block of mass 4 kg is suspended through two light spring balances A and B. Then A and B will read respectively 

(1) 4 kg and zero kg

(2) Zero kg and 4 kg

(3) 4 kg and 4 kg

(4) 2 kg and 2 kg