U can also add solar energy and hydro energy. Solar energy is by using the sun, while hydro is by using the force of water.
This is how hydro energy works:
its is usually built near a waterfall, OK so when the water falls of the cliff of the water fall , it creates a force which helps turn the generator and then it is carried into poles of electricity.
Hope this helps plus i gave u extra point Good luck :)
Complete question is;
Marie observed people at a store. Which is a qualitative observation she may have made?
A. Twenty people walked into the store.
B. The store sells clothes.
C. It was 1:00 P.M.
D. all of the above
Answer:
Option B:The store sells clothes.
Explanation:
We want to find the one that is a qualitative observation;
Looking at the options;
A. Twenty people walked into the store. This denotes a quantitative measure because of the number 20.
B. The store sells clothes. This denotes a qualitative measure because it describes what she sells.
C. This is a quantitative measure because it deals with time of 1 pm which is quantitative.
Therefore, the correct answer is Option B
Kinetic energy than parked
Answer:
3.6 m/s
Explanation:
From the law of conservation of momentum,
Total momentum before jump = Total momentum after jump
<em>Note: Before Dan jump off the skateboard, they where both moving with the same velocity</em>
u(m+m') = mv+m'v'................. Equation 1
Where m = Dan's mass, m' = mass of the skateboard, u = common velocity before the jump, v = Dan's final velocity, v' = The final velocity of the skateboard.
make v the subject of the equation
v = [u(m+m')-m'v')]/m.............. Equation 2
Given: u = 4.0 m/s, m = 50 kg, m' = 5 kg, v' = 8 m/s
Substitute into equation 2
v = [4(50+5)-(5×8)]/50
v = (220-40)/50
v = 180/50
v = 3.6 m/s
