Which of the following is not an example of doing work?

a. holding a tray in the cafeteria line
b. picking up a box off the floor
c. raising a barbell over your head
d. pushing a box across the floor

i will give brainliest to the first person who answers if they get it right
plz

Aprojectile is launched horizontally 10m above the ground and with an initial velocity of 15 m/s. a) determine the magnitude and direction of projectile velocity at t= 1.3s b) determine the magnitude and direction of projectile acceleration at t=1.3s

A248-g piece of copper is dropped into 390 ml of water at 22.6 °c. the final temperature of the water was measured as 39.9 °c. calculate the initial temperature of the piece of copper. assume that all heat transfer occurs between the copper and the water. remember, the density of water is 1.0 g/m

Which feature of a heating curve indicates a change ofn state