Which is a characteristic of a physical change? (1 point) a

The chemical bonds in the substance are unchanged.

b

The change cannot be seen.

c

The molecules all move at the same speed.

d

The substance has reacted with another substance.

An engineer designs a roller coaster so that a car travels horizontally for 162 ft, then climbs 127 ft at an angle of 31.0° above the horizontal. it then moves 127 ft at an angle of 46.0° below the horizontal. if we take the initial horizontal motion of the car to be along the +x-axis, what is the car's displacement? (give the magnitude of your answer, in ft, to at least four significant figures and give the direction of your answer in degrees counterclockwise from the +x-axis.)

We put a force of 50n on an object and the acceleration is 100 m/s². what is the mass of the object?

The earth exerts a gravitational force of 500 n on amy. what is amy’s mass in kg?