What evidence of a chemical change is observed when rust forms on iron

What is the potential energy of a 25 kg bicycle resting at the top of a hill 3 m high? (Formula: PE = mgh) 0 75 J 735 J O 245 J 0 37.8 J

Two objects of the same mass move along the same line in opposite directions. The first mass is moving with speed. The objects collide, stick together, and move with speed 0.100 in the direction of the velocity of the first mass before the collision.

The same ball is shot straight up a second time from the same gun, but this time the spring is compressed only half as far before firing. How far up does the ball go this time? Neglect friction.

By applying a 12-newton horizontal force, a 7-kilogram block is moved 12 meters in 3 seconds on a frictionless, horizontal surface. How much power was used in moving the block. A) 144 watts B) 112 watts C) 16 watts D) 48 watts

Lisa made the electromagnet shown. What can Lisa do to increase the strength of the electromagnet? She can use a nail with weaker magnetic properties. She can change the direction of the nail. She can move the wire loops closer together.

a box has mass 60 kg and it is lying on the earth surface occupying an area of 6000 CM square then the pressure exerted by it on the ground is equal to

A 16.0 kg canoe moving to the left at 12.5 m/s makes an elastic head-on collision with a 14.0 kg raft moving to the right at 16.0 m/s. After the collision, the raft moves to the left at 14.4 m/s. Disregard any effects of the water.

How many significant figures does the number 91010.0 have?

Convert 9.75 millimeters to centimeters.

A 4357 kg roller coaster car starts from rest at the top of a 36.5 m high track. determine the speed of the car at the top of a loop that is 10.8 m high