Science (English Medium) इयत्ता ११ - CBSE Question Bank Solutions for Physics

At what distance should two charges, each equal to 1 C, be placed so that the force between them equals your weight ?

Two spherical bodies, each of mass 50 kg, are placed at a separation of 20 cm. Equal charges are placed on the bodies and it is found that the force of Coulomb repulsion equals the gravitational attraction in magnitude. Find the magnitude of the charge placed on either body.

A monkey is sitting on a tree limb. The limb exerts a normal force of 48 N and a frictional force of 20 N. Find the magnitude of the total force exerted by the limb on the monkey.

A body builder exerts a force of 150 N against a bullworker and compresses it by 20 cm. Calculate the spring constant of the spring in the bullworker.

A satellite is projected vertically upwards from an earth station. At what height above the earth's surface will the force on the satellite due to the earth be reduced to half its value at the earth station? (Radius of the earth is 6400 km.)

The momentum p of a particle changes with time t according to the relation
\[\frac{dp}{dt} = \left( 10 N \right) + \left( 2 N/s \right)t\] If the momentum is zero at t = 0, what will the momentum be at t = 10 s?

Two charged particles placed at a separation of 20 cm exert 20 N of Coulomb force on each other. What will be the force of the separation is increased to 25 cm?

The force with which the earth attracts an object is called the weight of the object. Calculate the weight of the moon from the following data : The universal constant of gravitation G = 6.67 × 11⁻¹¹ N−m²/kg², mass of the moon = 7.36 × 10²² kg, mass of the earth = 6 × 10²⁴ kg and the distance between the earth and the moon = 3.8 × 10⁵ km. 

Find the ratio of the magnitude of the electric force to the gravitational force acting between two protons.

The average separation between the proton and the electron in a hydrogen atom in ground state is 5.3 × 10⁻¹¹ m. (a) Calculate the Coulomb force between them at this separation. (b) When the atom goes into its first excited state the average separation between the proton and the electron increases to four times its value in the ground state. What is the Coulomb force in this state?

The thickness of a glass plate is measured to be 2.17 mm, 2.17 mm and 2.18 mm at three different places. Find the average thickness of the plate from this data.

A person drops a coin. Describe the path of the coin as seen by the person if he is in

1. a car moving at constant velocity and
2. in a free falling elevator.

You are travelling in a car. The driver suddenly applies the brakes and you are pushed forward. Why does this happen?

An object is placed far away from all the objects that can exert force on it. A frame of reference is constructed by taking the origin and axes fixed in this object. Will the frame be necessarily inertial?

Suppose you are running fast in a field and suddenly find a snake in front of you. You stop quickly. Which force is responsible for your deceleration?

A spy jumps from an airplane with his parachute. The spy accelerates downward for some time when the parachute opens. The acceleration is suddenly checked and the spy slowly falls to the ground. Explain the action of the parachute in checking the acceleration.

When a horse pulls a cart, the force that helps the horse to move forward is the force exerted by

A car accelerates on a horizontal road due to the force exerted by.

A block of mass m is placed on a smooth wedge of inclination θ. The whole system is accelerated horizontally so that the block does not slip on the wedge. The force exerted by the wedge on the block has a magnitude.

Two objects A and B are thrown upward simultaneously with the same speed. The mass of A is greater than that of B. Suppose the air exerts a constant and equal force of resistance on the two bodies.