Question

A 2 kg mass is raised to a height of 2m.
- How much work was done on the mass?
- if the mass is released, how fast will it be traveling after falling for 2m if air resistance is ignored?

Answer 1

1) The work done on the mass is 39.2 J

2) The final velocity of the mass is 6.3 m/s

Explanation:

1)

The work done in lifting an object is equal to the gravitational potential energy gained by the object, therefore:

$W=U=mg\Delta h$

where

m is the mass of the object

g is the acceleration of gravity

$\Delta h$ is the change in height of the object

In this problem, we have

m = 2 kg

$g=9.8 m/s^2$

$\Delta h = 2 m$

So, the work done on the mass is

$W=(2)(9.8)(2)=39.2 J$

2)

For an object in free fall (=only gravity is acting on it), which is moving at constant acceleration, we can use the following suvat equation:

$v^2-u^2=2as$

where

v is the final velocity

u is the initial velocity

a is the acceleration

s is the distance covered

For the mass dropped in this problem,

u = 0

$a=g=9.8 m/s^2$ (acceleration of gravity)

s = 2 m

Solving for v, we find its final velocity:

$v=\sqrt{u^2+2as}=\sqrt{0+2(9.8)(2)}=6.3 m/s$

Learn more about work and gravitational potential energy here:

brainly.com/question/6763771

brainly.com/question/6443626

brainly.com/question/1198647

brainly.com/question/10770261

And about free fall here:

brainly.com/question/1748290

brainly.com/question/11042118

brainly.com/question/2455974

brainly.com/question/2607086

#LearnwithBrainly