1.) How much potential energy does an object with a mass of 3 kg have on top of a stand 12 meters high have on earth with a gravitational acceleration of 9.8 m/s, assuming no air friction?
a.) 3.673 Joules
b.) 352.8 Joules
c.) 39.2 Joules
d.) 2.45 Joules

What effects result when there is an impact between earth and an asteroid? check all that apply. a.massive flooding. b.extinction of many life forms.c.major earthquakes change in average global temperature.d. giant dust cloud

Acentrifuge in a medical laboratory rotates at an angular speed of 3,700 rev/min. when switched off, it rotates through 54.0 revolutions before coming to rest. find the constant angular acceleration (in rad/s2) of the centrifuge. your response is within 10% of the correct value. this may be due to roundoff error, or you could have a mistake in your calculation. carry out all intermediate results to at least four-digit accuracy to minimize roundoff error. rad/s2

Am i correct on these two physics questions?