Explain when a falling object is in free fall.

An object moved 45 meters in 9 seconds, what is the speed?

Scientific theories can be changed or replaced when

Because of interstellar dust, astronomers can see at most about 5 kpc into the disk of the galaxy at visual wavelengths.

A 72 kg sled Is pulled forward from rest by a snowmobile and accelerates at 2 m/s squared forward for five seconds. The force of friction acting on the sled is 120 N backwards. The total mass of the snowmobile and driver is 450 kg.

The position of an object moving along the x axis is given by x (t) = 2t^2+t^3 + 1, where x is in meters and t in seconds. The acceleration of the object at t = 2 seconds is: 4m/s?

Which safety measures should you follow during a thunderstorm? Check all that apply. (A) Avoid touching anything that conducts electricity. (B) Avoid touching a person who has been struck by lightning. (C) Go outside.

1. An automobile with a mass of 1000 kg accelerates when the traffic light turns green. If the net force on the car is 4000 N, what is the car's acceleration?

Imagine that you replace the block in the video with a happy or sad ball identical to the one used as a pendulum, so that the sad ball strikes a sad ball and the happy ball strikes a happy ball.

Under what conditions will an object experience a gravitational force? Under what conditions will an object experience an electric force? Under what conditions will an object experience a magnetic force?

A basketball player pushes down with a force of 34 N on a basketball that is inflated to a gauge pressure of 9 x 104 Pa. What is the diameter of contact between the ball! and the floor?