Question

You are pulling a sled using a horizontal rèpe, as shown in the diagram. The rope pulls the sled. exerting a force of 50 N to the right. The snow exerts a friction force of 30 N on the sled to the left. The mass of the sled is 50 kg.
Find the sun of the force on the self

Determine the acceleration of the sled

If the sled has an initial velocity 2m/s to the right, how fast will it be traveling after 5 seconds?

Answer 1

Answer:

Part 1

20 N

Part 2

0.4 m/s²

Part 3

4 m/s

Explanation:

The force which pulls the sled right = 50 N

The friction force exterted towards left by the snow = -30 N

The mass of the sled = 50 kg

Part 1

The sum of the forces on the sled, F = 50 N + (-30) N = 20 N

Part 2

The acceleration of the sled is given as follows;

F = m·a

Where;

m = The mass of the sled

a = The accelertion

a = F/m

∴ a = (20 N)/(50 kg) = 0.4 m/s²

The acceleration of the sled, a = 0.4 m/s²

Part 3

The initial velocity of the sled, u = 2 m/s

The kinematic equation of motion to determine the speed of the sled is v = u + a·t

The speed, v, of the sled after t = 5 seconds is therefore;

v = 2 m/s + 0.4 m/s² × 5 s = 4 m/s.