Thread: weight and mass

1.) In an emergency stop to avoid an accident, a shoulder strap seatbelt hold a 60 kg firmly in place if the car were initially traveling at 90 km/h and came to a stop 5.5 s along a straight level road, what was the average force applied to the passenger by the seatbelt?

2.) A 75.0 kg person is standing on a scale in an elevator. What is the reading of the scale in N (Newtons) if the elevator is (a) at rest, (b) moving up at a constant of 2.00 m/s, and (c) accelerating up at 2.00 m/s²?

TIA!

Originally Posted by John 5

1.) In an emergency stop to avoid an accident, a shoulder strap seatbelt hold a 60 kg firmly in place if the car were initially traveling at 90 km/h and came to a stop 5.5 s along a straight level road, what was the average force applied to the passenger by the seatbelt?

Average accelaertion is a = (90000/3600)/5.5 ~= 4.545 m/s^2.

Force is ma, so is 60*4.545 ~= 272.7 newtons

RonL

Originally Posted by John 5

2.) A 75.0 kg person is standing on a scale in an elevator. What is the reading of the scale in N (Newtons) if the elevator is (a) at rest, (b) moving up at a constant of 2.00 m/s, and (c) accelerating up at 2.00 m/s²?

TIA!

a) mg

b) mg

c) m(g+2)

RonL