Gravitation — Physics STD 11 Science — Question

Why does a child feel more pain when she falls down on a hard cement floor, than when she falls on the soft muddy ground in the garden?

Two particles A and B start from rest and move for equal time on a straight line. The particle A has an acceleration a for the first half of the total time and 2a for the second half. The particle B has an acceleration 2a for the first half and a for the second half. Which particle has covered larger distance?

Is it possible that a body have a constant velocity but varying speed?

A box is pushed through 4.0m across a floor offering 100N resistance. How much work is done by the resisting force?

Why is it not necessary for a body following another to stop, to avoid collision?

The temperature gradient in a rod 0.5m long is 80°C per metre. The temperature of the hotter end is 30°C. What is the temperature of the colder end?

Among the following quantities, select such pairs which have the same dimensions; momentum, angular velocity, torque, pressure, impulse, surface tension, stress, work, frequency, force constant.

State, for each of the following physical quantities, if it is a scalar or a vector : volume, mass, speed, acceleration, density, number of moles, velocity, angular frequency, displacement, angular velocity.

A particle is in linear simple harmonic motion between two points, A and B, 10cm apart. Take the direction from A to B as the positive direction and give the signs of velocity, acceleration and force on the particle when it is:

At the mid-point of AB going towards A.

What would happen if the force of gravity were to disappear suddenly?