Average velocity =
(displacement) / (time for the displacement)
and
(direction of the displacement) .
Displacement =
(distance from the start-point to the end-point)
and
(direction from the start-point to the end-point) .
When Ben is 200 meters from the corner store,
he is (500 - 200) = 300 meters from his house.
His displacement is
300 meters in the direction
from his house to the neighbor .
His average velocity is
(300/910) = 0.33 meters per second, in the
direction from his house to the neighbor .
Answer:
972 J
Explanation:
At the bottom, all the gravitational potential energy was converted into kinetic energy. If you calculate the GPE, its value will be the same that the KE at the bottom. The GPE can be calculated this way:
GPE = mass×gravity×heigth
GPE = 2.2×9.8×45.08 ≈ 972
Answer:
She does a work of 689.44 J in the snow.
Explanation:
A force is said to do work when it alters the state of motion of a body. The work of the force on that body will be equivalent to the energy needed to move it.
In other words, Work is a form of energy transmission between bodies. In order to carry out work, a force must be exerted on a body and it must move.
The work is equal to the product of the force times the distance and the cosine of the angle that exists between the direction of the force and the direction that the moving point or object travels:
W= F*d* cos Ф
Work W is measured in joules (J), force is measured in newtons (N), and displacement in meters (m).
In this case:
- F= 180 N
- d=5 m
- Ф= 40 degrees
Replacing:
W= 180 N*5 m* cos 40
Solving:
W= 689.44 J
<u><em>She does a work of 689.44 J in the snow.</em></u>
Answer:
33 g.
Explanation:
Assuming no heat transfer can be possible except for heat exchange between water and steel, we can say that the heat lost by the knife, must be equal to the heat gained by the water.
As we have a limit for the maximum temperature of both elements (once reached a final thermal equilibrium), of 100ºC, which means that the maximum allowable change in temperature will be of 300º C for the knife, and of 80º C for the water.
Empirically , it has been showed that for a heat exchange process using only conduction, the heat needed to raise the temperature of a body, is proportional to the mass, being the proportionality constant a factor that depends on the material, called specific heat.
So, we can write the following equation:
cs*mk*Δtk = cw*mw*Δtw
Replacing by the givens of the question, we have:
0.11 cal/gºC * 80 g * 300ºC = 1 cal/gºC*mw*80ºC
Solving for mw = 2,640 cal / 80 cal/g =33 g.
