Which of the following is a definite indicator of a chemical change?

A.

The shape of a substance is changed.

B.

A new substance is formed.

C.

A substance is converted from a liquid to a gas.

D.

The change in a substance is reversible.

In order for work to take place the energy present must be related to the movement of the object. a. the force applied must be a balanced force resulting in motion of the object. b. the force applied must cause the movement of the object c.

A 58-kg skater is standing still in front of a wall. By pushing against the wall she propels herself backward with a velocity of - 1 m/s. Her hands are in contact with the wall for 0.80 s. Ignore friction and wind resistance.

A 60kg student is sitting in a chair and is not moving. what is the force of a student acting on the chair? what is the force of the chair acting on the student?

An alternator provides 20 A of peak current at 100 V peak AC to a resistive electric heater. How much heating power is delivered to the load?

How could you increase the potential energy of the apple?

Velocity is: а - speed and direction. b - distance divided by time. c - always the same as speed. distance multiplied by time. d - distance multiplied by time

The gauge pressure in each of the four tires of an automobile is 230 kpa. if each tire has a "footprint" of 180 cm2 (area touching the ground), determine the mass of the car.

A bus travels 20 KM and 30 minutes what is average speed of the bus

What is the total number of atoms in the following formula? CaBr2

A lifeguard on a beach observes that waves have a speed of 7 m/s and a distance of 4.6m between wave crests. what is the period of the wave motion?