A body of mass 5 kg uniformly retards from 40 m s to 10 m s in 10 s . Calculate the retarding force.

Given, mass of the body m = 5 kg Initial velocity u = 40 m s . Final velocity v = 10 m s Time interval t = 10 s From newton's second law, Force exerted on the body is given by, F = m v - u t → 1 , Substituting the values in equation 1 we get, F = 5 ( 10 - 40 ) 10 ⇒ F = - 15 N So retarding force acting on the body is - 15 N .

A certain force exerted for 1 . 2 seconds raises the speed of an object from 1 . 8 m s to 4 . 2 m s . Find the acceleration. If mass of the object was 5 . 5 kg . Calculate the force applied.

Given, mass of the body m = 5 . 5 kg Initial velocity u = 1 . 8 m s Final velocity v = 4 . 2 m s Time interval t = 1 . 2 s From newton's second law, the force exerted on the body is given by, F = m v - u t → 1 , Substituting the values in equation 1 we get, F = 5 . 5 ( 4 . 2 - 1 . 8 ) 1 . 2 ⇒ F = 11 N From Newton's second law F = ma , a = 11 5 . 5 ⇒ a = 2 m s 2

A force of 2 N acting on a body changes its velocity uniformly from 2 m s to 5 m s in 10 s . Calculate the mass of the body.

Given, initial velocity u = 2 m s Final velocity v = 5 m s Time interval t = 10 s Force acting on the body F = 2 N From newton's second law, force acting on the body is given by, F = m v - u t → 1 , substituting the values in equation 1 we get, 2 = m ( 5 - 2 ) 10 ⇒ m = 20 3 kg ⇒ m = 6 . 67 kg

A body of mass 10 kg moving with a velocity of 25 m s comes to rest in 10 s . Find the change in momentum.

Given, mass of the body m = 10 kg Initial velocity u = 25 m s Final velocity v = 0 m s Time interval t = 10 s Change in momentum is given by equation m ( v - u ) → 1 Substituting the above values in equation, we get 10 0 - 25 = - 250 kg m s

E M B I B E

Essentials of PHYSICS Class IX>Chapter 2 - Forces and Laws of Motion>Practice Problems

Priyanka B Solutions for Chapter: Forces and Laws of Motion, Exercise 1: Practice Problems

Author:Priyanka B

Priyanka B Physics Solutions for Exercise - Priyanka B Solutions for Chapter: Forces and Laws of Motion, Exercise 1: Practice Problems

Attempt the practice questions on Chapter 2: Forces and Laws of Motion, Exercise 1: Practice Problems with hints and solutions to strengthen your understanding. Essentials of PHYSICS Class IX solutions are prepared by Experienced Embibe Experts.

Questions from Priyanka B Solutions for Chapter: Forces and Laws of Motion, Exercise 1: Practice Problems with Hints & Solutions

EASY

9th CBSE

IMPORTANT

Essentials of PHYSICS Class IX>Chapter 2 - Forces and Laws of Motion>Practice Problems>Q 5

A $1000 kg$ vehicle moving with a speed of $20 \frac{m}{s}$ is brought to rest in a distance of $50 m$ .

(i) find the acceleration.

(ii) calculate the unbalanced force.

(iii) the actual force applied may be slightly less than the calculated in (ii) Why? Give reason.

EASY

9th CBSE

IMPORTANT

Essentials of PHYSICS Class IX>Chapter 2 - Forces and Laws of Motion>Practice Problems>Q 7

A body of mass $5 kg$ uniformly retards from $40 \frac{m}{s}$ to $10 \frac{m}{s}$ in $10 s$ . Calculate the retarding force.

EASY

9th CBSE

IMPORTANT

Essentials of PHYSICS Class IX>Chapter 2 - Forces and Laws of Motion>Practice Problems>Q 9

A body of mass $10 kg$ is moving with a velocity of $20 {ms}^{- 1}$ . A force is applied on the body for $25 s$ , and it attains a velocity of $40 {ms}^{- 1}$ . What is the force applied?

EASY

9th CBSE

IMPORTANT

Essentials of PHYSICS Class IX>Chapter 2 - Forces and Laws of Motion>Practice Problems>Q 10

A certain force exerted for $1.2$ seconds raises the speed of an object from $1.8 \frac{m}{s}$ to $4.2 \frac{m}{s}$ . Find the acceleration. If mass of the object was $5.5 kg$ . Calculate the force applied.

EASY

9th CBSE

IMPORTANT

Essentials of PHYSICS Class IX>Chapter 2 - Forces and Laws of Motion>Practice Problems>Q 12

A force of $2 N$ acting on a body changes its velocity uniformly from $2 \frac{m}{s}$ to $5 \frac{m}{s}$ in $10 s$ . Calculate the mass of the body.

EASY

9th CBSE

IMPORTANT

Essentials of PHYSICS Class IX>Chapter 2 - Forces and Laws of Motion>Practice Problems>Q 13

If $20 N$ force is applied on a $50 kg$ body in $0.5$ second, find the impulse of the force given to the body.

EASY

9th CBSE

IMPORTANT

Essentials of PHYSICS Class IX>Chapter 2 - Forces and Laws of Motion>Practice Problems>Q 14

A cricket ball of mass $0.2 kg$ moving with a velocity of $20 m / s$ is brought to rest by a player in $0.1 s$ . Find the impulse of the ball and the average force applied by the player.