Answer:
90J
Explanation:
The only time work is being done is when he lifts the box off the ground. Therefore, using the work formula, 2 x 45, you get 90J. Hope this helps someone.
Answer:
3.body
Explanation:
Both P and S waves are both body waves. Body waves are waves that travels through the earth.
P and S waves are elastic seismic waves that moves within the earth. Love and Rayleigh waves are surface waves that travels through the surface.
- P waves is also known as primary waves
- S waves are known secondary waves.
These waves are the first set of waves to arrive a seismic station before the surface waves are picked up.
Answer:
Unknown
Explanation:
Because we cannot observe space beyond the edge of the observable universe, it is unknown whether the size of the Universe in its totality is finite or infinite.
The trough. The crest is compressed.
Answer:

Explanation:
The acceleration of an object is equal to the change in velocity of the object divided by the time taken for the object to change the velocity:

where:
u is the initial velocity
v is the final velocity
t is the time taken for the velocity to change from u to v
For Ms Jackson in this problem, we have:
u = 6 m/s (initial velocity)
v = 0 m/s (final velocity)
t = 4 s (time elapsed)
Substituting into the equation, we find the acceleration:

And the negative sign indicates that the direction of the acceleration is opposite to the direction of motion.