Acrate of apples weighing 71.4 n sits at rest on a ramp that runs from the ground to the bed of a truck. the ramp is inclined at 20.0° to the ground. what is the interaction partner of normal force?
1. if the interaction partner is acting above the surface of the ramp, enter a positive value.
2. if the interaction partner is acting below the surface of the ramp, enter a negative value.

Thomas his older brothers, who own a junk yard, on the weekends to earn extra money. he likes to them push broken-down cars to the back of the junk yard because it makes him feel strong. last saturday, they pushed three cars with different weights, and he noticed he used different amounts of force for each one. the cars were the following weights: white car: 2,700 kg red car: 1,500 kg blue car: 2,100 kg think about how much force is needed to move each car. which correctly lists the cars in order from the most to least amount of force needed to move them? a) white, blue, red b) blue, red, white c) red, white, blue d) white, red, blue

Consider a system to be two train cars traveling toward each other. what is the total momentum of the system before the train cars collide?   kg • what must the total momentum of the system be after the train cars collide?   kg •  

What is the equation for electrical work?