Question

a 50 kg crate is pushed across flat ground by a worker at a constant velocity. the crate experiences a friction force from the floor in the opposite direction of its motion. if the applied force on the crate by the worker is equal to 100 newtons in the direction of the crates motion, what must the friction force on the crate be equal to?

○ 9.8 newtons

○ 100 newtons

○ 490 newtons

○ 50 newtons

Explanation:

Step1: Recall Newton's First Law

If an object moves at constant velocity, the net force on it is zero ($F_{net} = 0$).

Step2: Analyze Forces on Crate

The applied force ($F_{applied}$) is 100 N (in motion direction), friction force ($F_{friction}$) is opposite. So $F_{net} = F_{applied} - F_{friction} = 0$.

Step3: Solve for Friction Force

From $F_{applied} = F_{friction}$, substitute $F_{applied} = 100$ N. Thus, $F_{friction} = 100$ N.

Answer:

100 Newtons (the option: 100 Newtons)