How Do You Calculate Initial Velocity with Kinetic Friction?

In summary, a baseball player weighing 81 kg slides into second base with a coefficient of kinetic friction of 0.49 between him and the ground. The magnitude of the frictional force is 389 N. To find his initial velocity, the equation F = ma can be used since the player's mass and time are known. There is no other force acting on the player, so the frictional force is the only force to consider.
  • #1
ayreia
6
0

Homework Statement



An 81-kg baseball player slides into second base. The coefficient of kinetic friction between the player and the ground is 0.49. (a) What is the magnitude of the frictional force? (b) If the player comes to rest after 1.6 s, what was his initial velocity?

Homework Equations



F = ma, Vo = Vf - at

The Attempt at a Solution



I already got 389 N for (a), now I'm just stuck on (b). Since I have his mass, Vf, and time, all I need is his acceleration to find Vo. I think I have to use F = ma, but I have no idea how to find the horizontal FNET. Ff is 389 N, but since I don't have his forward force, I don't know where to go from here. Thanks for the help!
 
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  • #2
What makes you think there is a force on him other than the friction force?
 
  • #3
Oh, so, since he's coming to a stop, there's only a frictional force?
 

FAQ: How Do You Calculate Initial Velocity with Kinetic Friction?

What is kinetic friction?

Kinetic friction is the force that opposes the motion of an object as it slides or moves along a surface.

How does kinetic friction differ from static friction?

Kinetic friction occurs when an object is already in motion, while static friction occurs when an object is at rest and trying to be set in motion.

How is kinetic friction affected by the velocity of an object?

The amount of kinetic friction is directly proportional to the velocity of the object. As the velocity increases, so does the kinetic friction.

Can the surface of an object affect the amount of kinetic friction?

Yes, the roughness or smoothness of a surface can affect the amount of kinetic friction. Rough surfaces will have a higher kinetic friction compared to smooth surfaces.

How can the coefficient of kinetic friction be calculated?

The coefficient of kinetic friction can be calculated by dividing the kinetic friction force by the normal force. This value is dependent on the types of materials in contact and their surface characteristics.

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