You visited us 2 times! Enjoying our articles? Unlock Full Access!

Byju's Answer

Standard XII

Physics

Problem Solving

The velocity ...

Question

The velocity of block just after collision is:

10 m / s

No worries! We‘ve got your back. Try BYJU‘S free classes today!

17.4 m / s

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

2.5 m / s

No worries! We‘ve got your back. Try BYJU‘S free classes today!

3 m / s

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is B $17.4 m / s$

$x = l - l cos θ$
Conservation of energy,
$m g (l - l cos θ)$
$= \frac{1}{2} m v^{2}$
$\Rightarrow v = 2 g l (1 - cos θ)$
$= 2 \times 10 \times 2.5 (1 - cos 60)$
$= 34.80 m / s$
Conservation of momentum,
$\Rightarrow m v + m \times 0 = 2 m \times v_{f}$
$\Rightarrow v = 2 v_{f}$
$v_{f} = \frac{v}{2}$
$= 17.42 m / s$
Hence, solved.

Suggest Corrections

Similar questions

Q. A ball of mass

3 kg

is moving with velocity

1.5 m/s

towards a heavy block which is moving towards the ball with velocity

0.5 m/s

as shown in the figure. Assuming the collision to be elastic, the velocity of the ball immediately after the collision is

Q. Two balls of mass

3 kg

and

6 kg

are moving towards each other with velocities

6 m/s

and

3 m/s

respectively on a frictionless surface. After colliding, the

3 kg

ball returns with velocity

3 m/s

. Velocity of

6 kg

ball (after collision) and coefficient of restitution are respectively:

Q. Figure below shows two blocks of masses 5 kg and 2 kg placed on a frictionless surface and connected with a spring. An external kick gives a velocity of 14 m/s to the heavier block in the direction of lighter one. Deduce (a) velocity gained by the centre of mass and (b) the separate velocities of the two blocks in the centre of mass coordinates just after the kick.

Two blocks $A$ and $B$ having the same mass collide elastically with each other. the velocity of block $A$ before the collision is $10 m/s$ . If block $A$ comes to rest after collision, then what was the velocity of block $B$ before the collision?

Q. On a smooth surface there are five identical equally spaced balls A, B, C, D and E present with initial velocities 10m/s, -5m/s, 2m/s, -3m/s, 3m/s respectively, Collision between any two ball assumed to be elastic. Then after all possible collision which pair of balls will have same speed as of initial

Join BYJU'S Learning Program

The velocity of block just after collision is:

The correct option is B 17.4m/sx=l−lcosθConservation of energy,mg(l−lcosθ)=12mv2⇒v=2gl(1−cosθ) =2×10×2.5(1−cos60) =34.80m/sConservation of momentum,⇒mv+m×0=2m×vf⇒v=2vf vf=v2 =17.42m/sHence, solved.