# CBSE Class 11-Physics: Laws of Motion and Friction Assignment 1

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**Question 1:**

A body of Mass moves along the such that a time its position is given by following expression

Where a, b and c are constant

(a) Calculate the acceleration of the body

(b) What is the force acting on it

(c) What is the force at

(d) What is the dimension of a

**Question 2:**

An object is subjected to three forces

(a) Find the acceleration of the object

(b) If the object starts from rest from origin, what will be the location after 4 sec

(c) What is the magnitude of resultant force and its direction

(d) What fourth force should be applied on the body to make the net resultant force zero

**Question 3:**

Consider a three-body system shown in figure below

(1) Find the acceleration of each objects

(2) Find the contact force between all the objects

**Question 4:**

Three Block of mass and are connected as shown in the figure below.

All the surfaces are frictionless, and strings and pulley are light.

Find the acceleration of all masses

**Question 5:**

A small block of is placed at rest on a larger block of mass . The situation is given in the figure below

The coefficient of friction between the two block is

And the horizontal surface is smooth A constant Force F is applied on the block

Find out the following

a) Find the value of limiting friction between the two blocks

b) What is the maximum acceleration by which the upper block can move

c) What is the maximum value of F at which both the block moves together

d) if N, what is the acceleration of each block and what frictional force is acting

between the block

h) If the force is applied to the upper block, what will be the minimum force required so

that there is relative motion between the block

Given

**Question 6:**

βAn object of mass M is standing in a stationary lift. What pressure force N exerted by the

object on the floor of the lift

a) If the lift is stationary

b) if the lift is moving upward with acceleration a

c) If the lift is moving downward with acceleration a

d) If the lift is falling freely

e) If the lift moving upward with constant velocity

f) If the lift is moving downward with constant velocity

**Question 7:**

A piece of uniform strings hangs vertically so that its free end just touches the horizontal surface of the. The upper end of the strings is now released. Show that at any instant during the falling of string. The total force on the surface of the table is three times the weight of the part of the string lying on the surface

**Question 8:**

Three block A, B, C are such as

They are connected as shown in the below figure.

The coefficient of friction between the block and table is

Find out the following

a) Draw all the forces acting on the system

b) The acceleration of the system

c) Frictional force between the block and table

d) Tension in the cord on the left and tension in the cord on the right

Given

The pulley is light and friction less

**Question 9:**

A boxcar is moving such that Initial velocity

And Acceleration i. Two objects A and B of mass is kept in the boxcar.

Take

Find out following

a) If the object A slid along the frictionless floor with the velocity i. Find out the equation of the motion of object from the frame of reference of Boxcar. Also, what time would it take to reach it original position relative to box car

b) The object B slid along the rough floor with the velocity i. Find out the equation of the motion of object from the frame of reference of Boxcar. Coefficient of sliding friction , Coefficient of static friction