Answer:
0.231 N
Explanation:
To get from rest to angular speed of 6.37 rad/s within 9.87s, the angular acceleration of the rod must be
If the rod is rotating about a perpendicular axis at one of its end, then it's momentum inertia must be:
According to Newton 2nd law, the torque required to exert on this rod to achieve such angular acceleration is
So the force acting on the other end to generate this torque mush be:
Answer:
Change in potential energy is 700.7 J.
Explanation:
Given:
Mass of the object is, kg
Height to which the object is raised above his head, m
Acceleration due to gravity is, m/s²
We know that for a mass raised to a height
, the change in potential energy is given as:
, where,
Now, plug in the given values and solve.
Therefore, the change in the potential energy is 700.7 J.
a. 4.52 m/s south
Velocity is a vector, whose magnitude is defined as the ratio between the displacement of the object and the time taken for the displacement to occur:
where
d is the displacement
t is the time
Velocity is a vector, so it also has a direction, which corresponds to that of the displacement.
For the ball in this problem,
d = 9.5 m south
t = 2.1 s
Substituting, we find:
and the directiion is the same as the displacement (south).
b. 4.52 m/s north
For this part, we must keep in mind that the speed is the magnitude of the velocity; however, speed is a scalar, so it does not have a direction.
Here we are told that the tennis ball travels at constant speed, so on its way back from Liam to Katie the ball's velocity is still the same as before, therefore
However, this time the direction is opposite to before, since the ball is travelling in the opposite direction.
Therefore, the ball's velocity when Liam returns Katie's service is
4.52 m/s north