When does an object have negative velocity

An astronaut is in space with a baseball and a bowling balL The astronaut gives both objects an equal push in the samedirection.

Why is alpha rays not suitable to scan baggage at the airport?

A child goes down a slide with an initial height of 4m. What is his speed at the bottom of the slide?

What can be used to describe the quantitative data

A 0.20-f capacitor is desired. what area must the plates have if they are to be separated by a 3.2-mm air gap?

A wave has a wavelength of 50 m and a speed of 200 m/s. What is the frequency of this wave in hertz?

A 75.0 kg person stands on a scale in an elevator. (a) What does the scale read (in N and in kg) when the elevator is at rest?

Which of the following best describes the earth's average surface temperature for the past 900,000 years? A. a steady warming trend B. fairly steady temperatures until recently C. prolonged periods of cooling and warming D.

A capacitor with initial charge q0 is discharged through a resistor. What multiple of the time constant τ gives the time the capacitor takes to lose (a) the first 1/8-th of its charge (b) 7/8-th of its charge?

A sheet of paper has a mass of 5 grams. The paper is dropped from a high building twice (it reaches terminal speed in both cases), once as a flat paper of area 600 cm2 and once crumpled as a ball of radius 2 cm.