A 61 kg skateboarder is moving down a ramp with a 7 m radius of curvature. At the bottom of this ramp, she reaches a speed of 7.8 m/s. What upward force acts on the skateboarder at the bottom of the ramp?

Arowboat passenger uses an oar to push the boat off the dock by exerting a force of 40n for 3.0s. what impulse acts on the boat.

Adiver named jacques observes a bubble of air rising from the bottom of a lake (where the absolute pressure is 3.50 atm) to the surface (where the pressure is 1.00 atm). the temperature at the bottom is 4.00 ∘c, and the temperature at the surface is 23.0 ∘c.what is the ratio of the volume of the bubble as it reaches the surface (vs) to its volume at the bottom (vb)? if jaques were to hold his breath the air in his lungs would be kept at a constant temperature. would it be safe for jacques to hold his breath while ascending from the bottom of the lake to the surface?

Bahan yang digunakan mencegah terjadinya polarisasi pada batu baterai a.larutan h2so4b.mncl2 dan serbuk karbonc.pbso4d.nh4cl