A metal rod is placed so that it connects a heat source at 50°C and a heat sink at 20°C. During time, t, an amount of heat, Q. is transferred from the source to the sink. If the
metal rod is replaced by another rod made of the same material, but of twice the length, how much heat will be transferred during the same amount of time, t?
A.1/2Q
B.4Q
C.1/4Q
D.2Q

Which fators influence ocean currents

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.

What is the force that opposes motion and works against the downward pull? a) friction b) gravity c) weight d) acceleration