27. A 0.150 kg baseball is thrown upward with an initial
1 answer:
Answer:
a.
b.
Explanation:
Given:
Mass of the baseball =
The initial velocity of the baseball = 20m/s
The force acting on the baseball is only due to gravity and the air resistance is negligible. The baseball acceleration is constant due to gravity.
According to Newton's second law:
----------(1)
where mass of the baseball
Put all the value in equation 1.
Therefore, the force on the ball when it reaches half of its maximum height is .
Similarly, the force acting on the ball when its peak .
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Answer:
Approximately (given that the magnitude of this charge is
.)
Explanation:
If a charge of magnitude is placed in an electric field of magnitude
, the magnitude of the electrostatic force on that charge would be
.
The magnitude of this charge is . Apply the unit conversion
:
.
An electric field of magnitude would exert on this charge a force with a magnitude of:
.
Note that the electric charge in this question is negative. Hence, electrostatic force on this charge would be opposite in direction to the the electric field. Since the electric field points due south, the electrostatic force on this charge would point due north.
Imagine an object is moving in one dimension on a number line, and for this we'll say that the numbers on the line are a metre apart. If the object moves from 2 m to 7 m, the change in position is 7-2=+5 metres. But if the object moves back from 7 m to 2 m, the change in position is 2-7=-5 metres. since 
, and time is always positive, velocity will be positive in one direction and negative in the other direction.