21. If aluminum's density is 2.7g/cm', find the volume of a 1150g sample.

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

From the question we have

We have the final answer as

Hope this helps you

explanation:

v=uf/(u-f)

= 5.-10/(5+10) convex lens has negative focal length

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards