Which of the following would increase the strength of an electromagnet

Carlota does 2000 J of work on a machine. The machine does 500 J of work. What is the efficiency of the machine? 4% 25% 75% 400%

Electric energy can be stored by what kind of charges

f 720-nm and 620-nm light passes through two slits 0.68 mm apart, how far apart are the second-order fringes for these two wavelengths on a screen 1.0 m away

What is one advantage of using primary source when doing research on an experiment

A car (mass 1 kg) on a frictionless track collides with a stationary car (mass 0.5 kg). The velocity of the first car before the collision is 2 m/s. The velocity of the 1st car after the collision is 1 m/s.

A fisherman noticed that a float makes 30 oscillations in 15 seconds. The distance between two consecutive crests is 2 m. What is the period and frequency of the wave? What is the wave speed?

A small spaceship with a mass of only 2.6 ✕ 103 kg (including an astronaut) is drifting in outer space with negligible gravitational forces acting on it. If the astronaut turns on a 12 kW laser beam, what speed will the ship attain in 1.

What will be the acceleration of a skydiver when air resistance builds up to 86% of her weight? assume the acceleration due to gravity is 10 m/s 2. answer in units of m/s 2?

A 255 g lead ball at a temperature of 81.6°C is placed in a light calorimeter containing 153 g of water at 22.3°C. Find the equilibrium temperature of the system.

Using the equation T=2π√L/g solve for L