A ball is dropped from a tower that is 400 m tall. Assuming only gravitational force g = 9.8 m/sec2, how long does it take to reach the ground? (Round your answer to one decimal place.) What is the speed upon impact? (Round your answer to one decimal place.)

Aliens declare war on Earth by dropping an asteroid on our planet.  The asteroid starts at rest from a distance of 37 x 106 m from the center of Earth.  Calculate the speed with which the asteroid hits Earth's surface, in km/s.  Use that G = 6.7 x 10-11 N m2 / kg2, MEarth = 6 x 1024 kg, and REarth = 6 x 106 m. (Please answer to the fourth decimal place - i.e 14.3225)

On a planet whose radius is 1.80 × 104 km, the acceleration due to gravity is 16.5 m/s?. What is the mass of the planet?

The separation distance between two 1.0 kg masses is changed. How is the mutual gravitational force affected in each case? (Assume F2 represents the new force and F1 represents the original force.) (a) The separation distance is two-fifths the original distance.F2 / F1 =  (b) The separation distance is 8 times the original distance.F2 / F1 =

The separation distance between two 1.0 kg masses is changed. How is the mutual gravitational force affected in each case? (Assume F2 represents the new force and F1 represents the original force.) (a) The separation distance is three-fourths the original distance.F2 / F1 = (b) The separation distance is 7 times the original distance.F2 / F1 =

I keep getting this wrong despite working it out many times. Can I please get some insight on the right approach? A team of astronauts is on a mission to land on and explore a large asteroid. In addition to collecting samples and performing experiments, one of their tasks is to demonstrate the concept of the escape speed by throwing rocks straight up at various initial speeds. With what minimum initial speed ?esc will the rocks need to be thrown in order for them never to "fall" back to the asteroid? Assume that the asteroid is approximately spherical, with an average density ?=3.32×106 g/m3 and volume ?=2.40×1012 m3 . Recall that the universal gravitational constant is ?=6.67×10−11 N·m2/kg2 . Answer in m/s

A cart is sliding down an inclined track. Suppose the track is 1.5 meters long and 30 cm tall at its end and has a gravitational acceleration of 1.962m/s2. Assuming it begins from rest, calculate the time it would take a cart to roll down the entire track.

An astronaut standing on Earth's surface has a weight of 700 N (about 157 lbs). He then takes a rocket ship to a distant planet with a mass twice as large as Earth and a radius 50% larger than Earth's radius. How much does the astronaut weigh on this new planet (in Newtons)? 7.

At the surface of planet X, a 1 kg object weighs 4 N (planet radius R=106m). A space probe passes by planet X with the nearest point (A) at 8R from the center. When the probe was very far away it had a speed of sqrt(2gxR), where gx is the acceleration of gravity at the planet surface. Find a value for the speed of this probe when it is at point A, vA.

A car driving around a circular track has a centripetal acceleration of 97 m/s2 until it hits a slick spot and slides straight off the track. If the radius of the track is 61 m, what is the car's speed v when it leaves the track?