Answer:
It is D (20 N in direction of boy’s push; 4 m/s/s)
Explanation:
<u>F=ma</u>
F: force
m: mass
a: acceleration
"5 kg box" means the box was 5 kg in mass
"force of 25 N and 5 N frictional force" means the box had force of 25 N and opposite force of 5 N. Let's say the box moved to right with 25 N. Think as integers. 25 to the right means positive. On a number line, the right side has positive numbers while left side has negative numbers. So since it moved to the RIGHT it means positive 25. But there was a frictional force of 5 to the opposite side. If you add 25 and -5, you will get 20. 25+(-5) is same as 25-5. So now you have 20 N, but we don't know the acceleration, so leave that as a variable. Then plug into the equation.
F=ma
20=5a
divide both sides by 5
4=a
the acceleration of the box was 4m/s/s
Answer:
The magnitude of car A acceleration is 4 times that of car E
Explanation:
Assuming they are traveling at a constant speed. Their (centripetal) acceleration is as the following
where v is the (linear) velocity and r is the radius. We can use this to calculate their ratio
Since and
So the magnitude of car A acceleration is 4 times that of car E
Answer:
To increase the volume of moving water, impoundments or dams are used to collect the water. An opening in the dam uses gravity to drop water down a pipe called a penstock. The moving water causes the turbine to spin, which causes magnets inside a generator to rotate and create electricity.
Answer:
(A) The wavelength of this wave is .
(B) The amplitude of this wave is .
Explanation:
Refer to the diagram attached. A point on this wave is at a crest or a trough if its distance from the equilibrium position is at a maximum.
The amplitude of a wave is the maximum displacement of each point from the equilibrium position. That's the same as the vertical distance between the crest (or the trough) and the equilibrium position.
- On the diagram, the distance between the two gray dashed lines is the vertical distance between a crest and a trough. According to the question, that distance is for the wave in this rope.
- On the other hand, the distance between either gray dashed line and the black dashed line is the distance between a crest (or a trough) and the equilibrium position. That's the amplitude of this wave.
Therefore, the amplitude of the wave is exactly the vertical distance between a crest and a trough. Hence, for the wave in this question,
.
The wavelength of a transverse wave is the same as the minimum (horizontal) distance between two crests or two troughs. That's twice the horizontal distance between a crest and a trough in the same period.
.
Answer:
3,500,000 J
Explanation:
WORK = POWER * TIME
WORK= 5400 * 640
=6456000 J = 3,500,000 J