A hockey puck is sliding across a frozen pond with an initial speed of 6.5 m/s. It comes to rest after sliding a distance of 7.6 m. What is the coefficient of kinetic friction between the puck and the ice?
I know this one is not that difficult. However, I can't seem to get the correct answer. Any help is much apprectiated.
Initial puck kinetic energy
= work done against friction
(1/2) M V^2 = M*g*muk*X
muk is the coefficient of kinetic friction that you want. M cancels out, so you don't need to know it.
X is the distance that the puck slides while coming to a stop.
muk = (1/2) V^2/(g X)
That's all there is to it!
Ahh ok, I didn't realize the masses cancel out. But of course you're right.
That really was easy. :)
To find the coefficient of kinetic friction between the puck and the ice, we can use the equation:
friction force = coefficient of kinetic friction x normal force
In this case, the normal force is equal to the weight of the puck, which can be calculated using the formula:
weight = mass x acceleration due to gravity
First, we need to find the mass of the puck. We can use the equation:
force = mass x acceleration
Since the only force acting on the puck is the force of friction, we can write:
force = friction force
From the given information, we know the initial speed of the puck and the distance it slides before coming to rest. We can use the equation:
final velocity^2 = initial velocity^2 + 2 x acceleration x distance
Since the puck comes to rest, the final velocity is 0 m/s. Plugging in the given values, we have:
0 = (6.5 m/s)^2 + 2 x acceleration x 7.6 m
Solving for acceleration, we find:
acceleration = -((6.5 m/s)^2) / (2 x 7.6 m)
Now, we can find the mass of the puck using the equation:
force = mass x acceleration
The force is equal to the weight of the puck, so we have:
weight = mass x acceleration
Solving for mass, we find:
mass = weight / acceleration
Finally, we can substitute the mass and acceleration back into the equation for friction force:
friction force = coefficient of kinetic friction x weight
Solving for the coefficient of kinetic friction, we find:
coefficient of kinetic friction = friction force / weight
By plugging in the values we calculated, we can find the coefficient of kinetic friction between the puck and the ice.
given:mass m= 20 kilogram ,force = 50 N from newton 2nd law,
f=ma where a=acceleration of the box
a=f over m= 50 over 20=2.5