Question

A body of mass 2 kg moving with a uniform velocity of 5 m/s is acted upon a force of 15 N. Calculate it's velocity after 2 seconds​

Answer 1

Explanation:

Our interest is in finding the moment when the velocity along X-axis becomes zero. So noting the initial velocity along X-axis as u=6m/s

Acceleration along X-axis is Force along X-axis/mass=−3/5=−0.6m/s

2

Time taken in making the velocity along X-axis to zero is change in velocity/acceleration=

(−0.6)

(0−6)

=10second

Answer 2

Answer:

Explanation:

The graph is given between force and time.

Area under Force-time graph gives Impulse.  

So, Total area in 20s is

A  

2

​

=  

2

1

​

×5×20

=50m  

2

 

A  

1

​

=20×5=100m  

2

 

A  

3

​

=  

2

1

​

×10×(−20)=−100m  

2

 

Therefore total area A=A  

1

​

+A  

2

​

+A  

3

​

 

A= 50m  

2

 

Work done W= F×s

=(F×t)×v

    Initial velocity is given, v=$$5m/s$$                

  Work done, W=Ft.v

           W= 50 x 5 J

            = 250J