The electric motor has an input energy of 50,000 joules each second. The motor transfers 35,000 joules of useful energy each second. Calculate the efficiency of the electric motor (show workig out too)

What do all group 2 elements have in common? They all gain two electrons to form a stable outer energy level. They form covalent bonds with halogens. They all react easily with the noble gases. They tend to form ionic bonds by losing electrons

A ball of mass 0.440 kg moving east (+x direction) with a speed of 3.80 m/s collides head-on with a 0.220-kg ball at rest. If the collision is perfectly elastic, what will be the speed and direction of each ball after the collision?

What is 2.40 g/cm sinks or floats

15 grams of liquid plastic are frozen in a physical change that increases the volume. What can be known about the plastic after the change?

What is the purpose of zigzag line on a periodic table?

Suppose you squeeze a sponge into a small ball. does the mass of the sponge change? Does it's density change?

A solid round bar with diameter of 2-in has a groove cut to a diameter of 1.8-in, with a groove radius of 0.1-in. the bar is not rotating.

If a pilot pulls her 12.0 kg rollaboard suitcase along the ground with a force of 25. N for 10 M. The handle she pulls on makes an angle of 36.5 degrees with the horizontal. How much work does she do over the ten meter distance?

What happens to the density when water is poured into a empty glass?

A British newspaper was interested in whether groups of people who differed in social standing were treated differently when they complained to organizations about poor service they had received.