A student builds an electromagnet using a battery, an iron nail, and some insulated wire. The wire is wrapped around the nail 50 times, then connected to the battery. What changes could the student make to increase the strength of the electromagnet?
1. wrap more wire around the nail
2. increase the voltage of the battery
3. use a switch to turn the electromagnetic on and off
4. increase the size of the nail

A. 1 and 2
B. 2 and 4
C. 1,2 and 4
D. 1,2,and 3

You are about to open a container of soy milk but notice that there are instructions to “shake well before serving.” the soy milk is most likely a

Aballoon is rising vertically upwards at a velocity of 10m/s. when it is at a height of 45m from the ground, a parachute bails out from it. after 3s he opens his parachute and decelerates ata a constant rate 5m/s.when. (a) what was the height of the parachutist above the ground when he opened his parachute? (b)how far is the parachutist from the balloon at t=3s? (c)with what velocity does the parachutist hit the ground? (d)after how long does the parachutist hit the ground after his exist from the balloon?

If a hiker that weighs 600 newtons climbs a 50 meter hill, how much gravitational potential energy has the hiker gained?