Question

Two children are pulling and pushing a 30.0 kg sled. The child pulling the sled is exerting a force of 12.0 N at a 45o angle. The child pushing the sled is exerting a horizontal a force of 8.00 N. There is a force of friction of 5.00 N.
What is the weight of the sled?
What is the normal force exerted on the sled? Round the answer to the nearest whole number.
What is the acceleration of the sled? Round the answer to the nearest hundredth.

Answer 1

In order to calculate the weight, we may simply use:
W = mg
W = 30 * 9.81
W = 294.3 N

The sum of the reaction force and the upward component of child pulling will be equal to total downward force. The force acting downwards is the weight. Therefore:
R + 12sin(45) = 294.3
R = 285.82 N

The acceleration can be found using the resultant force and the mass of the sled. The resultant force is:
F(r) = pulling force + pushing force - friction
F(r) = 12cos(45) + 8 - 5
F(r) = 11.48 N
a = F/m
a = 11.48 / 30
a = 0.38 m/s²

Answer 2

The weight is: 294 N
The normal force is 286 N
The acceleration is: -0.38 m/s²