Answer:
The energy returns to the weightlifter's muscles, where it is dissipated as heat.
Explanation:
The energy returns to the weightlifter's muscles, where it is dissipated as heat. As long as the weightlifter controls the weight's descent, their muscles are acting as an overdamped shock absorber, as if the weight were sitting on a piston containing very thick fluid, slowly compressing it downward (and slightly heating up the fluid in the process). Since muscles are complicated biological systems and not simple pistons, they require metabolic energy to maintain tension throughout the controlled descent, so the weightlifter feels like they're putting energy into the weight, even though the weight's gravitational potential energy is being converted into heat within the lifter's muscles.
I believe it is the percent abundance. Isotopes are atoms of the same element with similar atomic number but different mass number. Natural abundance is the abundance of isotopes of a chemical element as naturally found on the planet. The relative atomic mass of these isotopes is the atomic weight listed for the element in the periodic table.
The average speed is 0.55 m/s
<h3>What was his displacement?</h3>
Displacement is defined as the change in position of an object.
Mathematically,
D = Initial value - Final Value
D = 30 - 5 = 25m
Now , We have to find the average velocity,
Average velocity is calculated by the formula V = D/t,
where V equals the average velocity, D equals total displacement and t equals total time.
V = D/t
V = 25 m / 45s
V = 0.55 m/s
So , The average speed is o.55 m/s
learn more about average speed:brainly.com/question/9834403
#SPJ1
Answer: 
Explanation:
The acceleration of an object can be calculated by using Newton's second law:

where
F is the net force applied on the object
m is the mass of the object
a is its acceleration
In this problem, we have F=125 N and m=25.0 kg, so we can rearrange the equation to calculate the acceleration:

Left and right to a point called ad focal point after passing through convex lens