20. suppose you needed to raise a 250-kg mower a distance of 6.0 cm above the ground to change a tire. if you had a 2.0-m long lever,
where would you place the fulcrum if your force was limited to 300 n?

1.78 m

Explanation:

er the fulcrum placed at a distance r from the force.

mass, m = 250 kg

Force, F = 300 N

As the  net torque is zero, so clockwise torque = anticlockwise torque

300 x r = 250 x 9.8 ( 2 - r )

300 x r = 2450 x (2 - r)

300 r = 4900 - 2450 r

2750 r = 4900

r = 1.78 m

Thus, the fulcrum is placed at a distance of 1.78 m from the force.

temp rises, and expansion

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s