An athlete is working out in the weight room. he steadily holds 50 kilograms above his head for 10 seconds. which statement is true about this situation?

a) the athlete isn’t doing any work because he doesn’t move the weight.
b)the athlete isn’t doing any work because he doesn’t hold the weight long enough.
c) the athlete is doing work because he prevents the weight from falling downward.

d)the athlete is doing work because 50 kilograms is a significant load to lift.

Acalorimeter uses the principle that thermal energy flows from hotter material to colder material until both reach the same

Which of the choices are parts of an atom? select all that apply. a.) compound b.) electron c.) neutron d.) molecule e.) photon f.) proton g.) element

Aplayground slide is 8.80 ft long and makes an angle of 25.0° with the horizontal. a 63.0-kg child, initially at the top, slides all the way down to the bottom of the slide. (a) choosing the bottom of the slide as the reference configuration, what is the system's potential energy when the child is at the top and at the bottom of the slide? what is the change in potential energy as the child slides from the top to the bottom of the slide? (include the sign of the value in your answer.)