A 40 kg mass is dropped from a tall rooftop and accelerates at 9.8 m/s2

. What is the weight of

the dropped object?

A) 392 N

B) 9.8 N

C) 40 N

D) 0 N

For an unknown sample of the experiment, students measure 1668 counts when they first receive their sample and 1330 counts 5 minutes later. Calculate the half-life t1/2 t 1/2 of their sample.

Which scientist studies the earth's core, the mantle, the crust, continents, and the ocean floor? a geologist a meteorologist an oceanographer an astronomer

In the table below, which statement would best fill the missing box under "Closed System"? Open System Closed System Matter freely moves Matter does not freely move Energy freely moves Energy is unknown Energy is destroyed Energy does not freely

Two electrons exert a force of repulsion of 1.2 N on each other. How far apart are they? The elementary charge is 1.602 * 10-19 C and Coulomb's constant is 8.987 * 109 N · m2/C2. Answer in units of m.

At a country music festival in New Hampshire, the Oak Ridge Boys are playing at the end of a crowded 184-m field when Ronny Fairchild hits a note on the keyboard that has a frequency of 400. Hz.

What is a lever used for?

What did the romans build as a step toward environment management

Accelerations are produced by equal forces or unequal forces?

A wave travels through a medium. As the wave passes, the particles of the medium vibrate in a direction perpendicular to the direction of the wave's motion. The wave is a. longitudinal. c. electromagnetic. b. a pulse. d. transverse.

Two carts undergo an inelastic collision where they stick together. Cart A has an initial velocity v0, and the second cart B is initially at rest.