When a force causes a body to move, work is done on the object by the force. Work is the measure of the energy transfer when a force 'F' moves an object through a distance 'd'. So we say that energy is transferred from one energy store to another when work is done, and therefore, energy transferred = work done.
Answer:
Explanation:
2. The image formed in a diverging lens is always virtual.
4. Converging lenses are shaped such that a beam of parallel light rays passing through the lens will be brought together in one single point.
If the box is moving at constant velocity, net force must be zero, so:
F + fr = 0
fr = -F
<u>fr = -40 N</u>
Answer:
a) 103.32 m
b) 9.18 s
Explanation:
a) Let's use the knowledge that at the top of its trajectory, the baseball will have a final velocity of 0 m/s.
The acceleration due to gravity is -9.8 m/s², assuming the upwards direction is positive and the downwards direction is negative.
The initial velocity of the baseball is 45 m/s.
We are trying to find the vertical displacement of the baseball, Δx, and we have the variables v, a, and v₀.
Find the constant acceleration equation that contains all four of these variables:
Substitute the known values into the equation.
- (0)² = (45)² + 2(-9.8)Δx
- 0 = 2025 - 19.6Δx
- -2025 = -19.6Δx
- Δx = 103.32
The maximum height of the ball before it falls back down is 103.32 m.
b) Now we want to solve for time t. Find a constant acceleration equation that contains three known variables.
Substitute known values into this equation.
- 0 = 45 + (-9.8)t
- -45 = -9.8t
- t = 4.59183673
Remember that this is only half of the baseball's flight since we are using the final velocity for when the ball is halfway through its trajectory.
To solve for the total time the baseball is in the air, double the time t we solved for.
The baseball is in the air for 9.18 s.
