Phase Change
Time (min) Temperature (oC)
0 15
1 32
2 45
3 48
4 54
5 54
6 54
7 54
8 54
9 59
10 60

A certain substance is a solid at 15°C. Sarah heated a sample of the solid substance in a beaker using a Bunsen burner during science class. She and her partner recorded the temperature at one-minute intervals. Their data is recorded in the table below. Based on the girls' data, when was the kinetic energy of the substance the greatest?

An inclined plane wrapped around a metal shaft is a a. lever b. screw c. pulley d. wedge

For problems 1-3, consider a simple dc brush motor with a permanent magnet stator. with an an consider a simple dc brush motor with a permanent magnet ae supply voltage of 100 v, the no-load speed of the motor is 1000 rpm. this motor can provide a torque of 1.9 n-m at 800 rpm drawing a current of 2 a current are both zero at no load.) 1. with an armature supply voltage of 100 v, the motor is operated at 900 rpm. what is the motor torque? what is the mechanical power delivered by the motor? what is the current draw? what is the electrical power input? what is the energy efficiency of the motor? with an armature supply voltage of 100 v, the motor is operated at 1100 rpm (where it acts as a generator). what torque input is required? what mechanical power is required what current is generated? what is the electrical power generated? what is the energy efficiency of the motor acting as a generator? 2. with an armature supply voltage raised to 120 v, the motor is operated at 1000 rpm. what is the no-load speed? what is the motor torque? what is the mechanical power delivered by the motor? what is the current draw? what is the electrical power input what is the energy efficiency of the motor? 3.

1. a net force of 100 newton’s is applied to a wagon for 5 seconds. this causes the wagon to undergo a change in momentum of