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# Physics problem?

An empty sled of mass 25 kg slides down a muddy hill with a constant speed of 2.4 m/s.

The slope of the hill is inclined at an angle of 15° with the horizontal as shown in the

figure above.

a. Calculate the time it takes the sled to go 21 m down the slope.

b. On the dot below that represents the sled, draw/label a free-body diagram for the sled

as it slides down the slope

c. Calculate the frictional force on the sled as it slides down the slope

the figure shown isn't needed to answer the question, it's just a free body diagram that's not needed to solve the problem.

### 2 Answers

- oldprofLv 71 month agoFavorite Answer
An empty sled of mass M = 25 kg slides down a muddy hill with a constant speed of V = 2.4 m/s.

The slope of the hill is inclined at an angle of theta = 15° with the horizontal as shown in the

figure above.

a. Calculate the time it takes the sled to go S = 21 m down the slope.

S = VT; so T = S/V = 21/2.4 = 8.75 seconds. ANS

b. On the dot below that represents the sled, draw/label a free-body diagram for the sled as it slides down the slope N/A.

c. Calculate the frictional force on the sled as it slides down the slope

The force down the slope is w = W sin(theta) as A = 0 acceleration we can write f = w - F = W sin(theta) - F = 0 since f = MA = M0 = 0. That means the friction force F = W sin(theta) = Mg sin(theta) = 25*9.81*sin(radians(15)) = 63.5 N. ANS.