A crate with a mass of 110 kg glides through a space station with a speed of 2 m/s. An astronaut speeds it up by pushing on it from behind with a force of 240 N, continually pushing with this force through a distance of 4 m. The astronaut moves around to the front of the crate and slows the crate down by pushing backwards with a force of 230 N, backing up through a distance of 3 m. After these two maneuvers, what is the speed of the crate?

a)final speed ___________= m/s

and

question 2

A daredevil plans to bungee jump from a balloon 53.0 m above a carnival midway. He will use a uniform elastic cord, tied to a harness around his body, to stop his fall at a point 10.0 m above the ground. Model his body as a particle and the cord as having negligible mass and obeying Hooke's law. In a preliminary test, hanging at rest from a 5.00 m length of the cord, he finds that his body weight stretches it by 1.50 m. He will drop from rest at the point where the top end of a longer section of the cord is attached to the stationary balloon.

(a) What length of cord should he use?

___ m

(b) What maximum acceleration will he experience?

and question 3

The electric motor of a model train accelerates the train from rest to 0.755 m/s in 19.5 ms. The total mass of the train is 875 g. Find the average power delivered to the train during the acceleration.

___________ W

and question 4

A sled of mass m is given a kick on a frozen pond. The kick imparts to it an initial speed of 2.80 m/s. The coefficient of kinetic friction between sled and ice is 0.150. Use energy considerations to find the distance the sled moves before it stops.

_____________m

i have been sitting here trying these problems all day for past 7 hours and getting no where.

.

please show me how step by step so i can understand. im begging you please just spare 2 minutes to help me understand.