Answer:
It's A
Explanation:
Although I'm not sure about the second one, I'm sure the first one is A
Answer:
25J
Explanation:
power = work done ÷ time taken.
and work done = force applied × distance covered.
according to the question, the athlete lifts the weight of 100N upto 5m therefore;
100N × 5m = 500N/m
then onwards,
the work done (500 N/m) should be divided by the time taken to calculate the power,
500 ÷ 20s = 25J
is your answer.
hope this helped. :)
The best system to talk about would be a galaxy system. Energy does not enter the galaxy, but it does "recycle" its energy. For instance, when the life of a star comes to its end, it can go super nova. and all the energy from that star is then released back into the galaxy to form nebula's and then eventually into other stars. The energy inside of a galaxy can change frequently. It can be in the form of heat from a star, or it can change into gamma radiation from an explosion. Gases like helium and hydrogen come together and form a ball of gas creating the heat. Then the heat is dispersed leaving different types of radiation like gamma, ultra-violet, microwave, and infrared. Energy can leave a system by the local black holes. Black holes with shoot out Hawking radiation is when the black hole disperses its own energy out into space, also known as Black Hole Evaporation<span>. The energy from that black hole is then dispersed into the rest of the universe or possibly back into the galaxy from which it came from. </span>
Mass-Energy is constant. If you are working then you are doing it spending energy. If you have a working rate so u also have a energy spending rate, which is called the power. As footballers working rate is too high(running, kicking, jumping, tackling, defensing etc)their energy spending rate i.e, required power is also high. Hence to be a footballer you need high power.
