A radioactive isotope has a half-life of ten days. how much of a 100 gram sample will be left after 20 days

An object with a mass of 7.8 kg is pulled on a horizontal surface by a horizontal pull of 50 N to the right. The friction force on this object is 30 N to the left. What is the acceleration of the object? 0.16 m/s^2 10 m/s^2 2.6 m/s^2 6.4 m/s^2

At a certain altitude above the Earth's surface, the electric field has a magnitude of 135 V/m. How much energy is stored in 1.00 m3 of air due to this field?

A 60-turn coil has a diameter of 13 cm. The coil is placed in a spatially uniform magnetic field of magnitude 0.60 T so that the face of the coil and the magnetic field are perpendicular.

Which of the following is true of high clouds?

Two technicians are discussing oil and filter changes. Technician A says that there should be a gasket in place on a spin-on oil filter when removed, and if not, that you should make sure the gasket isn't stuck to the engine mount.

How would you describe the two projectors used to screen a three-dimensional movie? A. Both projectors have vertical polarizers. B. One projector has a vertical polarizer and the other has a horizontal polarizer. C.

A roller coaster has a mass of 500 kg. It drops from rest at the top of a hill that's 57 m tall. How fast is it going when it reaches the bottom? Acceleration due to gravity is g = 9.8 m/s2.

Two sinusoidal waves are moving through a medium in the positive x-direction, both having amplitudes of 7.00 cm, a wave number of k=3.00m-1, an angular frequency of ω=2.50s-1, and a period of 6.00 s, but one has a phase shift of an angle ϕ=π12rad.

For a vacation, you and your family fly east to west from Boston, Massachusetts, to Seattle, Washington. You notice that your flight back home to Boston is shorter than your flight to Seattle. Which phenomenon causes your flight home to be shorter?

You spy on an anchor on the bottom of a lake. What is the direction and amount of force the water exerts on it: a) zero b) up, equal to the weight of the anchor. c) up, less than the weight of the anchor d) down, equal to the weight of the anchor.