Question

A 2.0-kg projectile moves from its initial position to a point that is displaced 20 m horizontally and 15 m above its initial position. How much work is done by the gravitational force on the projectile

Answer 1

Answer:

W= - 300 J

Explanation:

Given that

Mass ,m= 2 kg

Horizontal distance ,x= 20 m

Vertical distance ,y= 15 m

As we know that gravity force always acts in the downward direction

F= m g

The displacement of the object is in upward direction

d= -15 m

The work done by a force given as

W= F.d

Now by putting the values

W= - 2 x 10 x 15                ( Take g= 10 m/s²)

W= - 20 x 15

W= - 300 J

Therefore the work done by gravitational force will be -300 J.

Answer 2

Answer:

W = 294 J

Explanation:

given,

mass of the projectile = 2 Kg

horizontal displacement = 20 m

vertical displacement = 15 m

work done by the gravitational force = ?

the work done by gravitational force only account for vertical motion.

force due to gravity =  m g

                                 = 2 x 9.8 = 19.6 N

work done is equal force x displacement

W = F x s

W = 19.6 x 15

W = 294 J