5) You are pushing a 55 kg refrigerator along at a constant speed of 1.5 m/s using an applied force of 250 N when the floor type changes from tile to carpet. The carpet has a coefficient of static friction of 0.62 and a coefficient of kinetic friction of 0.54. Are you pushing with enough force to keep the refrigerator moving?
No, because the force of static friction is greater than the pushing force
None of these explanations is correct
Yes, because it is already moving, it doesn't matter if the surface type changes because all surfaces have the same coefficient values
No, because it is moving at a constant speed so the net force is zero.
i'm thinking it is the 3rd option.
What made you think it is the third option? Did you do some calculations to justify this?
For the time being, ignore the static friction, assuming as you said, the refrigerator is already moving.
The normal reaction, N, on the carpet is mg.
The minimum force, F, to keep the refrigerator moving at a uniform speed is μmg, where μ is the coefficient of kinetic friction.
Does F exceed the current applied force of 250 N? The answer will lead you to the correct answer.
The correct answer is actually the first option: No, because the force of static friction is greater than the pushing force. Let me explain how to arrive at this answer.
To determine if you are pushing the refrigerator with enough force to keep it moving, we need to compare the applied force to the maximum static friction force. The maximum static friction force can be calculated using the formula:
F_static friction = coefficient of static friction * normal force
First, let's calculate the normal force. The normal force is the force exerted by a surface to support the weight of an object resting on it. In this case, the weight of the refrigerator is equal to:
weight = mass * acceleration due to gravity
= 55 kg * 9.8 m/s^2
= 539 N
Since the refrigerator is at rest, the normal force is equal to its weight:
normal force = weight = 539 N
Now, let's calculate the maximum static friction force using the given coefficient of static friction (0.62):
maximum static friction force = 0.62 * normal force
= 0.62 * 539 N
= 334.18 N (approximated to two decimal places)
Since the applied force of 250 N is less than the maximum static friction force of 334.18 N, the pushing force is not enough to keep the refrigerator moving on the carpet. Therefore, the correct answer is the first option: No, because the force of static friction is greater than the pushing force.