A lift is descending with a constant velocity 'v'.A man in the lift drops a coin. The coin experiences an acceleration towards the floor equal to:
g+v
g-v
g
zero
1N =
1kg m/s2
1kg/ms2
1kg/m/s2
1kg ms
A boy is standing in a lift. The force on the floor of the lift due to the weight of the boy becomes zero :
When the lift moves up with an acceleration of 9.8 ms2
When the lift moves down with an acceleration 9.8 ms-2
When the lift is not moving
When the lift moves either upwards or backwards
Water sprinkler used for grass lawns begins to rotate as soon as the water is supplied. Explain the principle on which it works.
Newton's 1st law of motion
Principle of conservation of momentum
Newton's 2nd law of motion
Newton's third law of motion
A ball of mass 100gm is moving with a velocity of 10ms-1. The force of the blow by the bat acts for 0.01 seconds.Calculate the average force exerted by the bat ?
100 N
200 N
300 N
400 N
A motor car is moving with a velocity of 108 km/h and it takes 4 s to stop after the brakes are applied.Calculate the force exerted by the brakes on the motor car if its mass along with the passengers in the motor car is 1000 kg.
- 8500 N
-7500 N
8500 N
7500 N
S.I unit of momentum is :
kg m/s2
kg m/s
kgm-1s-1
kgs
Which of the following relation of mass and acceleration is correct?
m1/m2 = a1/a2
m12/m22 = a2/a1
m1/m2 = a2/a1
m12/m22= a1/a2
When an object undergoes acceleration
Its speed always increases
Its velocity always increases.
It always falls towards the earth
A force always acts on it.
Which physical quantity can change the velocity of an object , direction of its motion and also shape and size?
Force
Momentum
Energy
Inertia
