A 4.1-kg block is pushed 2.1 m up a vertical wall with constant speed by a const

Question

A 4.1-kg block is pushed 2.1 m up a vertical wall with constant speed by a constant force of magnitude F applied at an angle of

= 30°

with the horizontal, as shown in the figure below. If the coefficient of kinetic friction between block and wall is 0.30, determine the following.

(a) the work done by

J

(b) the work done by the force of gravity
J

(c) the work done by the normal force between block and wall
J

(d) By how much does the gravitational potential energy increase during the block's motion?
J

PLEASE GIVE EQUATIONS AND EXPLAIN STEP BY STEP

Explanation / Answer

Mass of block, m = 4.1 Kg

Distance moved, S = 2.1 m vertically up

Since the velocity remains constant, the net force = 0

Upward force = F sin 30 = 0.5 F

Gravitational force = mg = 4.1*9.8 = 40.18 N

frictional force (down) = F cos 30*coefficient of kinetic friction = F cos 30 * 0.3

So, 0.5 F = 40.18 + 0.3 Cos 30 F

=> 0.24 F = 40.18

=> F = 167.42 N

A) Work done by force = F sin 30 * distance = 167.42 sin 30 * 2.1 = 175.79 J

B) Work done by gravity = - mg*distance = - 4.1*9.8*2.1 = - 84.378 J

C) Work done by normal force = 0 J (since normal and direction of motion are perpendicular)

D) Increase in gravitational potential energy = mg*distance = 4.1*9.8*2. = 84.378 J

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