Question

Velocity-time graph of a particle of mass 2 kg moving in a straight line is as shown in figure Work
done by all the forces on the particle is :
4 V (mis)
20
1 s)
2
(A)
400 J
(B)
-400 J
(C)
-200 J
(D
200 J​

Answer 1

Answer:

T

2

P

1

V

1

=

T

2

P

2

V

2

P

1

=1atm

V

1

=350cm

3

T

1

=273k

P

2

=0.5atm

T

2

=550k

V

2

=?

V

2

=

T

1

P

2

P

1

V

1

T

2

V

2

=1 × 350 ×550 / 273 × 0.5

V

2

= 1409 cm

3

Therefore B is the correct option.

Answer 2

Acceleration of the particle = a =

Δt

Δv

=

2

−20

=−10m/s

2

Distance travelled by particle before coming to rest=Area of the triangle=

2

1

×2×20m=20m

Thus the work done by forces=Fs=mas

=2×−10×20J=−400J