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

Which of the following measurements is most precise?

Figure shows the orientation of two vectors u and v in the XY plane.

If `u = ahati + bhatj` and `v = phati + qhatj`

which of the following is correct?

The component of a vector r along X-axis will have maximum value if ______.

A metre scale is moving with uniform velocity. This implies ______.

A cricket ball of mass 150 g has an initial velocity `u = (3hati + 4hatj)` m s⁻¹ and a final velocity `v = - (3hati + 4hatj)` m s⁻¹ after being hit. The change in momentum (final momentum-initial momentum) is (in kg m s¹)

In the previous problem (5.3), the magnitude of the momentum transferred during the hit is ______.

A hockey player is moving northward and suddenly turns westward with the same speed to avoid an opponent. The force that acts on the player is ______.

A body of mass 2 kg travels according to the law x(t) = pt + qt² + rt³ where p = 3 ms⁻¹, q = 4 ms⁻² and r = 5 ms⁻³. The force acting on the body at t = 2 seconds is ______.

The motion of a particle of mass m is given by x = 0 for t < 0 s, x(t) = A sin 4 pt for 0 < t < (1/4) s (A > o), and x = 0 for t > (1/4) s. Which of the following statements is true?

1. The force at t = (1/8) s on the particle is – 16π² Am.
2. The particle is acted upon by on impulse of magnitude 4π² A m at t = 0 s and t = (1/4) s.
3. The particle is not acted upon by any force.
4. The particle is not acted upon by a constant force.
5. There is no impulse acting on the particle.

The position time graph of a body of mass 2 kg is as given in figure. What is the impulse on the body at t = 0 s and t = 4 s.

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?

A woman throws an object of mass 500 g with a speed of 25 ms¹.

1. What is the impulse imparted to the object?
2. If the object hits a wall and rebounds with half the original speed, what is the change in momentum of the object?

Figure shows (x, t), (y, t ) diagram of a particle moving in 2-dimensions.

(a)

(b)

If the particle has a mass of 500 g, find the force (direction and magnitude) acting on the particle.

A bicyclist comes to a skidding stop in 10 m. During this process, the force on the bicycle due to the road is 200 N and is directly opposed to the motion. The work done by the cycle on the road is ______.

A body of mass 0.5 kg travels in a straight line with velocity v = a x^3/2 where a = 5 m^–1/2s^–1. The work done by the net force during its displacement from x = 0 to x = 2 m is ______.

A body is moving unidirectionally under the influence of a source of constant power supplying energy. Which of the diagrams shown in figure correctly shows the displacement-time curve for its motion?

A body is being raised to a height h from the surface of earth. What is the sign of work done by applied force?

A body is being raised to a height h from the surface of earth. What is the sign of work done by gravitational force?

A graph of potential energy V(x) verses x is shown in figure. A particle of energy E0 is executing motion in it. Draw graph of velocity and kinetic energy versus x for one complete cycle AFA.

A block of mass 1 kg is pushed up a surface inclined to horizontal at an angle of 30° by a force of 10 N parallel to the inclined surface (Figure). The coefficient of friction between block and the incline is 0.1. If the block is pushed up by 10 m along the incline, calulate

1. work done against gravity
2. work done against force of friction
3. increase in potential energy
4. increase in kinetic energy
5. work done by applied force.