An 8 Newton wooden block slides across a horizontal wooden floor at constant velocity. What is the magi notice of the force of k
1 answer:
Answer:
The force of kinetic friction between the block and the floor is 2.4 N
Explanation:
The given parameters are;
The weight of the block = 8 Newtons
The velocity of the block = Constant velocity
Taking the kinetic friction for wood, = 0.3, we have;
The normal reaction of the block on horizontal ground, N = The weight of the block = 8 N
The force of kinetic friction between , =
× N
Therefore, we have;
The force of kinetic friction between the block and the floor, = 0.3 × 8 N = 2.4 N.
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Answer:
A. 1.4 m/s to the left
Explanation:
To solve this problem we must use the principle of conservation of momentum. Let's define the velocity signs according to the direction, if the velocity is to the right, a positive sign will be introduced into the equation, if the velocity is to the left, a negative sign will be introduced into the equation. Two moments will be analyzed in this equation. The moment before the collision and the moment after the collision. The moment before the collision is taken to the left of the equation and the moment after the collision to the right, so we have:
where:
M = momentum [kg*m/s]
M = m*v
where:
m = mass [kg]
v = velocity [m/s]
where:
m1 = mass of the basketball = 0.5 [kg]
v1 = velocity of the basketball before the collision = 5 [m/s]
m2 = mass of the tennis ball = 0.05 [kg]
v2 = velocity of the tennis ball before the collision = - 30 [m/s]
v3 = velocity of the basketball after the collision [m/s]
v4 = velocity of the tennis ball after the collision = 34 [m/s]
Now replacing and solving:
(0.5*5) - (0.05*30) = (0.5*v3) + (0.05*34)
1 - (0.05*34) = 0.5*v3
- 0.7 = 0.5*v
v = - 1.4 [m/s]
The negative sign means that the movement is towards left