Question

question 7
1 pts
an object of mass \m\ moves across flat ground at some velocity and experiences a friction
force. if the objects mass is changed to 2m, how will the friction force change?
the friction force will double
the friction force will quadruple
the friction force will remain the same
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Explanation:

Step1: Recall the formula for friction force

The formula for friction force \(F_f=\mu N\), where \(\mu\) is the coefficient of friction (depends on the surfaces in contact, remains the same here as the ground and object's material don't change) and \(N = mg\) (normal force, \(m\) is mass, \(g\) is acceleration due to gravity). So \(F_f=\mu mg\).

Step2: Analyze the change when mass is \(2m\)

When \(m\) becomes \(2m\), the new friction force \(F_f'=\mu(2m)g = 2\mu mg\).

Answer:

The friction force will double.