Understanding Physics for JEE Main and Advanced Mechanics Part 1 by D C Pandey | 9789313190554 | 9313190559 | Holooly

Understanding Physics for JEE Main and Advanced Mechanics Part 1

273 SOLVED PROBLEMS

Question: 10.13

A particle is suspended from a fixed point by a string of length 5 m. It is projected from the equilibrium position with such a velocity that the string slackens after the particle has reached a height 8 m above the lowest point. Find the velocity of the particle, just before the string slackens. ...

Verified Answer:

At P, T = 0 ∴

m g \c...

Question: 10.11

A stone tied to a string of length L is whirled in a vertical circle with the other end of the string at the centre. At a certain instant of time the stone is at it lowest position and has a speed u. Find the magnitude of the change in its velocity as it reaches a position, where the string is ...

Verified Answer:

\begin{aligned} v=\sqrt{u^2-2 g h} &=\s...

Question: 10.10

Two blocks A and B of masses 1 kg and 3 kg are attached with two massless strings as shown in figure. The system is kept over a smooth table and it is rotated about the axis shown in figure with constant angular speed ω =2 rad/ s . Find direction and magnitude of centrifugal force on (a) A as ...

Verified Answer:

(a) Acceleration of B,

a_B=r_B \omega^2=(2)...

Question: 8.3

A block of mass m is attached with two strings as shown in figure. Draw the free body diagram of the block. ...

Verified Answer:

The free body diagram of the block is as shown in ...

Question: 9.SE.16

A single conservative force F (x ) acts on a 1.0 kg particle that moves along the x-axis. The potential energy U ( x ) is given by: U(x)=20+(x-2)² where, x is in meters. At x=5.0 m the particle has a kinetic energy of 20 J. (a) What is the mechanical energy of the system? (b) Make a plot of U (x) ...

Verified Answer:

(a) Potential energy at x = 5.0 m is

U=20+(...

Question: 9.SE.19

Two blocks of masses m = 5 kg and M = 10 kg are connected by a string passing over a pulley B as shown. Another string connects the centre of pulley B to the floor and passes over another pulley A as shown. An upward force F is applied at the centre of pulley A. Both the pulleys are massless. Find ...

Verified Answer:

Let m be the mass of B. From its free-body diagram...

Question: 9.SE.18

A small disc of mass m slides down a smooth hill of height h without initial velocity and gets onto a plank of mass M lying on a smooth horizontal plane at the base of hill figure. Due to friction between the disc and the plank, disc slows down and finally moves as one piece with the plank. (a) ...

Verified Answer:

(a) When the disc slides down and comes onto the p...

Question: 9.SE.17

A small disc A slides down with initial velocity equal to zero from the top of a smooth hill of height H having a horizontal portion. What must be the height of the horizontal portion h to ensure the maximum distance s covered by the disc? What is it equal to? ...

Verified Answer:

In order to obtain the velocity at point B, we app...

Question: 9.SE.15

A smooth track in the form of a quarter-circle of radius 6 m lies in the vertical plane. A ring of weight 4 N moves from P1 and P2 under the action of forces F F 1 2 , and F3 . Force F1 is always towards P2 and is always 20 N in magnitude; force F2 always acts horizontally and is always 30 N in ...

Verified Answer:

The work done by

F_1

is

W_1=...

Question: 9.SE.14

A small mass m starts from rest and slides down the smooth spherical surface of R. Assume zero potential energy at the top. Find (a) the change in potential energy, (b) the kinetic energy, (c) the speed of the mass as a function of the angle θ made by the radius through the mass with the vertical. ...

Verified Answer:

\text { In the figure, } h=R(1-\cos \theta)...

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