Firecracker question

[familyaerospace]

Ok, I am restudying for this test and am using firecracker.me since it'll force me to review things I've covered. I am not sure if this question has the wrong answer or if I am missing something.

A 5N force is applied to a box on the floor. The coefficient of static friction between the box and the floor is 0.5. The box weighs 12N. What is the force of static friction on the box?

A 10N
B 14N
C 5N
D 20N

Fs = us * Normal Force

If the normal force is equal to the weight it is 12 N
us = 0.5
Fs = ??

12 N*0.5 = 6 N is the max static friction which since 5 N is the force applied to the force, I would assume C is the correct answer

Firecracker lists the answer as 10 N but the explanation doesn't seem to make sense.

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[dudewheresmymd]

Must be a typo. Applied force = Force of Static friction up to the max static force. So you are right in saying the force of static friction is 5N when the applied force is 5N since 5N < 6N.

 

[Cawolf]

I agree. Their answer must be incorrect as it is not possible for the force of static friction to be greater than the applied force in that example.

 

[familyaerospace]

Thank you both for proving I am not completely physics incompetent!

I wonder if I can select that question to never show again.