Jessie was driving her 2000-kg Camry when she dropped her phone. She leaned down to pick it and just then a small child rode his bicycle into the street 45 meters in front of her. She is traveling at 15 m/s (about 30 mph). She sees the boy and slams on the brakes and the car comes to a stop with the bumper of the car just touching the tire of the bike. Whew!! Calculate the braking force of the car.

Awelder using a tank of volume 7.50×10^-2 m^3 fills it with oxygen (with a molar mass of 32.0 g/mol ) at a gauge pressure of 3.30×10^5 pa and temperature of 37.1 ∘c. the tank has a small leak, and in time some of the oxygen leaks out. on a day when the temperature is 23.1 ∘c, the gauge pressure of the oxygen in the tank is 2.00×10^5 pa . a) find the initial mass of oxygen. b) find the mass of oxygen that has leaked out.