Question

34. A constant force of 3.5 N accelerates a stationary body of mass 20 kg through
a displacement of 3.5 m. Find the work done,​

Answer 1

Answer:

Solution

Force F=2.5 N.

Mass of the particle m=15 g=0.015 kg

Displacement covered by the particles s=2.5 m.

Now, For Work,

Work Done = Force × Displacement

W=2.5×2.5

W=6.25J

Hence, the Work done by the Particles is 6.25 J.

Now, For Power,

Work Done = 6.25 J.

Initial Velocity u=0

Using Newton's second law of Motion,

F=ma

a=

F

m

a=

0.015

2.5

a=166.67m/s

2

Now, the time taken for the displacement is:

s=ut+

2

1

at

2

2.5=0+

2

1

×

3

500

×t

2

t=

500

5×3

=0.1

3

Now, Power = Work/Time.

P=

t

W

P=

0.1

3

6.25

P=36.08W

Hence, the work done is 6.25J and power is 36.08W

Explanation:

copy the method for 3.5

Answer 2

Answer:

12.25

Explanation:

given, force =3.5

displacement=3.5

hence, work done=force × displacement

work done = 3.5×3.5

= 12.25Nm*2