Answer:
<em>We need to (at least) apply a force of 9.8 N to move the block</em>
Explanation:
<u>Second Newton's Law</u>
If a net force 
different from zero is applied to an object of mass m, then it will move at an acceleration a, given by
If we apply a force F to an object placed on a rough surface, the only way to make it move is to beat the friction force which is given by
Where 
is the static friction coefficient and 
is the normal force exerted by the table to the object. Since there is no motion in the vertical direction the normal force equals the weight of the object:
The friction force is
Thus, we need to (at least) apply a force of 9.8 N to move the block
Answer:
A ball moving until gravity pulls it back down to the ground
Explanation:
Answer:
The magnitude of the force exerted by the ball on the catcher is 1.9 × 10² N
Explanation:
Hi there!
Let´s find the acceleration of the ball that makes it stop when caught by the catcher. The acceleration can be calculated from the equation of velocity considering that it is constant:
v = v0 + a · t
We know that initially the ball was traveling at 25 m/s, so, if we consider the position of the catcher as the origin of the frame of reference, then, v0 = -25 m/s. We also know that it takes the ball 20 ms (0.02 s) to stop (i.e. to reach a velocity of 0). Then using the equation of velocity:
v = v0 + a · t
0 m/s = -25 m/s + a · 0.020 s
25 m/s/ 0.020 s = a
Now, using the second law of Newton, we can calculate the force exerted by the catcher on the ball:
F = m · a
Where:
F = force.
m = mass of the ball.
a = acceleration.
F = 0.150 kg · (25 m/s/ 0.020 s) = 1.9 × 10² N
According to Newton´s third law, the force exerted by the ball on the catcher will be of equal magnitude but opposite direction. Then, the force exerted by the ball on the catcher will have a magnitude of 1.9 × 10² N.
Answer:
33627.4 N/m
Explanation:
By Hook's law F = k x
where F= force applied
K= Spring constant
x= distance it compresses.
Since the force applied in this case will be the weight of the object that causes it to compress, so, the weight will be (175 * 9.8) = 1715N force which causes a compression (x) of 0.0510m.
So,
F = K x
K = F / x
K = 1715 / 0.0510
K = 33627N/m
