Which of the following statements is true about tides? (2 points) tides are caused only by the moon. tides are not caused by the moon. tides are caused by the location of the earth, sun, and moon. the sun is not involved in causing tides. 2- which statement is true? (2 points) tides occur about an hour later each day. tides occur at the same time each day. tides occur about an hour earlier each day. tides do not happen at set times. 3- how much does the sun influence tides on earth? (2 points) several times as much as the moon twice as much as the moon about as much as the moon half as much as the moon

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.

Awave travels at a speed of 5.2 m/s. if the distance between crests is 0.40 m, what is the frequency of the wave? use f=v/wavelength a. 13 hz b. 2.1 hz c. 0.077 hz d. 5.6 hz

Consider a system with two masses that are moving away from each other. why will the kinetic energy differ if the frame of reference is a stationary observer or one of the masses?