There is a 30 g sample of Be-11. It has a half-life of about 14 seconds.

How much will be left after 28 seconds?

A. 3.75 g

B. 7.5 g

C. 15 g

D. 30 g

un objeto se lanza verticalmente hacia arriba con una velocidad de 40 km/h calcular el tiempo que tarda cuando alcanza su altura maxima

What factors affect the speed of a wave? Check all that apply.

When running a marathon what kind of energy transformation takes place

Fine grains of beach sand are assumed to be spheres of radius 38.9 µm. These grains are made of silicon dioxide which has a density of 2600 kg/m3 . What is the mass of each grain of sand? Answer in units of kg. ... ?

Alex collides with a desk as he runs through his office. If the combined momentum of Alex and the desk was 400 kg•m/s to the north before the collision, what is their combined momentum after the collision?

Suppose you increase your walking speed from 4 m/s to 12 m/s in a period of 1 s. What is your acceleration?

If a wave is traveling at a constant speed, and the frequency decreases, what would happen to the wavelength? A) It would increase B) It would decrease C) It would remain constant D) It would drop to zero

What conditions lead you to see an absorption line spectrum from a cloud of gas in interstellar space?

A car travels 35.0 mph north for 1.00 hour, then 40.0 mph east for 0.0500 hour, and finally 50.0 mph northeast for 2.00 hours. Calculate the average speed.

A 500 lb steel beam is lifted up by a crane to a height of 100 ft and is held there. A) How much work is being done to hold the beam in place? B) How much work was done to lift the beam?