Physics mechanics questions please help

1. a car moves at 20ms-1 straight east, the driver is wearing his safety belt. the front end crumples by 1.55m.( the car and the driver therefore continue moving forward for 1.55m before they come to rest

1.1 now if the driver has a mass of 72kg, what is the magnitude force exerted by the seatbelt on the driver during collision.\

1.2 if the total mass of the car is 550kg, determine the change in momentum during collision

2. bolts are screwed with a torque of 100Nm the spanner is 50cm in length

2.1 if the mechanical advantage is 1.2 determine the force applied on the bolt

3 an astronaut with a mass of 80kg has a weight of 800N when on earth. the moon ( mass 7.35 * 10 to the power 22)

3.1 calculate the weight on the moon if the radius of the moon is 1.75 * 10 to the power 6 m

1.1 First find the acceleration from d=v0*t + 1/2*a*t^2 and vf=v0+a*t. For the second equation 0=20m/s+a*t so solve for t=-20/a. Now substitute into first equation and get

d=v0*-20/a +1/2*a*(-20/a)^2 input the given values of v0 and and the equation becomes:

1.55m=20m/s*-20/a + 1/2*a*400/a^2 simplify to
1.55m=-400m/s /a + 200/a

solve for a=-129m/s

now, f=ma so f=72*129=9288N

Part 1.2
p=550kg*20m/s - 550kg*0m/s
p=11,000 kg*m/s


Part 2.1
F=100Nm/(0.5m*1.2) = 167N

Part 3.1
F=G*m1*m2/r^2
F=6.674(10^-11)*80*7.35(10^22)/(1.75(1…
F=128N