CBSE Class-9 Physics (Demo)

A block of mass 2 kg rests on a rough inclined plane making an angle of $$30^{\circ}$$ with the horizontal. If $$\mu_{\mathrm{s}}=0.7$$, the frictional force on the block is (Take $$\mathrm{g}=9.8 \mathrm{~m} / \mathrm{s}^{2}$$ )

A weight $$W$$ rests on a rough horizontal plane. If the angle of friction be $$\theta$$, the least force that will move the body along the plane will be

The minimum force required to move a body up an inclined plane of inclination $$30^{\circ}$$ is found to be thrice the minimum force required to prevent it from sliding down the plane. The coefficient of friction between the body and the plane is

A horizontal force, just sufficient to move a body of mass 4 kg lying on a rough horizontal surface is applied on it. The coefficients of static and kinetic friction between the body and the surface are 0.8 and 0.6 respectively. If the force continues to act even after the block has started moving, the acceleration of the block in $$\mathrm{ms}^{-2}$$ is $$\left[\mathrm{g}=10 \mathrm{~ms}^{-2}\right.$$ ]

The horizontal acceleration that should be given to a smooth inclined plane of angle $$\sin ^{-1}\left(\frac{1}{l}\right)$$ to keep an object stationary on the plane, relative to the inclined plane is

A body is sliding down a rough inclined plane. The coefficient of friction between the body and the plane is 0.5 . The ratio of the net force required for the body to slide down and the normal reaction on the body is $$1: 2$$. Then the angle of the inclined plane is

A particle is projected up along a rough inclined plane of inclination $$45^{\circ}$$ with the horizontal. If the coefficient of friction is 0.5 the retardation is [‘g’ be the acceleration due to gravity]

A body of weight 64 N is pushed with just enough force to start it moving across a horizontal floor and the same force continues to act afterwards. If the coefficients of static and dynamic friction are 0.6 and 0.4 respectively, the acceleration of the body will be

A body is sliding down an inclined plane having coefficient of friction 0.5. If the normal reaction is twice that of the resultant downward force along the incline, the angle between the inclined plane and the horizontal is

Two bodies having the same mass 2 kg each have different surface areas $$50 \mathrm{~m}^{2}$$ and $$100 \mathrm{~m}^{2}$$ in contact with a horizontal plane. If the coefficient of friction is 0.2 , the forces of friction that come into play when they are in motion will be in the ratio.

A block rests on a rough inclined plane making an angle of $$30^{\circ}$$ with the horizontal. The coefficient of static friction between the block and the plane is 0.8 . If the frictional force on the block is 10 N , the mass of the block (in kg ) is $$\left[\mathrm{g}=10 \mathrm{~ms}^{-2}\right]$$.

A block of mass $$\sqrt{3} \mathrm{~kg}$$ is kept on a frictional surface with $$\mu=1 / 2 \sqrt{3}$$. The minimum force to be applied (as shown) to move the block is [Take $$g=10 \mathrm{~m} / \mathrm{s}^{2}$$ ]

A marble block of mass 2 kg lying on ice when given a velocity of $$6 \mathrm{~m} / \mathrm{s}$$ is stopped by friction in 10s. Then the coefficient of friction is [Take $$\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^{2}$$ ]

A horizontal force of 10 N is necessary to just to hold a block stationary against a wall. The coefficient of friction between the block and the wall is 0.2 . The weight of the block is

A box is lying on an inclined plane. If the box sliding when the angle of inclination is $$60^{\circ}$$, then the coefficient of static friction between the box and the plane is

When a particle moves in a circle with a uniform speed

An object follows a curved path. The following quantities may remain constant during the motion

If a body subtends an angle of $$60^{\circ}$$ in 10 s , its angular velocity is $$\qquad$$

If angular velocity of Delhi is $$r$$ units, the angular velocity of Mumbai is $$\qquad$$ _.

Find the angular velocity of minutes hand of a clock.

A point on the wheel of 400 cm diameter has a velocity of $$1600 \mathrm{~cm} / \mathrm{s}$$. The angular velocity of the wheel is $$\qquad$$ .

What is the ratio of linear velocity to angular velocity of a particle moving in circular path circumference C?

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

A boy pushes a toy box 2.0 m along the floor by means of a force of 10 N directed downward at an angle of $$60^{\circ}$$ to the horizontal. The work done by the boy is ________

A person holds a bucket of weight 60 N . He walks 7 m along the horizontal and then climbs up a vertical distance of 5 m . The work done by the man is $$\qquad$$