Answer:
80%
Explanation:
The thermal energy output by the oven is 800 J which is the useful energy that can be utilized for cooking.
The electrical energy input to the oven is 1000 J.
The efficiency of the oven =
(Useful energy output)/(Total energy input to the oven) x 100
Hence, the efficiency of the oven is 80%.
Answer:
1) The car is slowing down
2) A = 40N forward & B = 25N up
Explanation:
Whenever you're dealing with forces on moving objects, it is important to look at each of the numbers and the directions they're going in.
With the racecar, we see it has four forces on it, 2,000 N up and down, 8,000 back, and 6,000 N forward. Now, each of these forces are going in their respective directions, but they are most in comparison with the force going in the opposite direction (vertical axis, horizontal axis). The two 2,000 N forces will cancel each other out since there is an equal force in both directions, causing a net force of <u>0 N on the vertical axis</u>. This is because the car is most likely moving on a flat surface. As for the horizontal axis, we simply subtract 6,000 & 8,000 to get a net force of <u>-2,000 N in the backwards direction</u>, telling us that the car is slowing down.
As for the boxes, we see the same vertical and horizontal axes, but separated to each box. Box A has a net force of <u>40 N in the forward direction</u> and Box B has a net force of <u>25 N in the upward direction</u>.
It's true, when we lift an object we add energy to it.
because, when we lift an object by applying force , the object attains a height and hence the energy gets stored in it, in the form gravitational potential energy .
