If a car accelerates at a uniform 4.0 m/s, how long will it take to reach a speed of 36.0 m/s,
1 answer:
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Answer:
<em>Answer: B. 49 N</em>
Explanation:
<u>Friction Force </u>
When an object is at rest on a rough surface, it encounters a friction force that opposes motion.
The friction force when an object is moving on a horizontal surface is calculated by:
Where is the coefficient of static friction and N is the normal force.
If no forces other then the weight and the normal are acting upon the y-direction, then the weight and the normal are equal in magnitude:
N = W = m.g
Thus, the friction force is:
We are given the coefficient of static friction and the mass of the object m=10 Kg. The minimum force needed to make it start moving is the maximum friction force:
Fr=0.5*10*9.8
Fr = 49 N
Answer: B. 49 N
