A student of mass 60.0 kg, starting at rest, slides down a slide 20.0 m long, tilted at an angle of 30.0° with respect to the horizontal. If the coefficient of kinetic friction between the student and the slide is 0.120, find (a) the force of kinetic friction, (b) the acceleration, and (c) the speed she is traveling when she reaches the bottom of the slide

Explanation:

Reaction force of inclined surface

R = mgcos30

=60 x 9.8 x .866

= 509 N

Force of kinetic friction

= .12 x 509

= 61.08 N

b )

net force downwards = mgsinθ - μmgcosθ

acceleration = g sinθ - μgcosθ

9.8 sin30 - .12 x 9.8 x cos30

= 4.9 - 1.018

a= 3.88 m /s²

c )

v² = 2as

= 2 x  3.88 x 20

v = 12.46 m /s

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.