A student at a skateboarding park is rolling on a skateboard down a ramp with a 26.0degree incline. (a) Consider the student and skateboard as a single unit and draw a free-body diagram to represent the forces present on the student and skateboard unit. (b) Explain what relationship must exist between the forces for the student to accelerate down the slope. (c) If the student and skateboard have a mass of 60.0 kg. what is the magnitude of the force of gravity parallel to the slope? (d) If the coefficient of kinetic friction in the wheels and bearings is 0.120 and the force of air friction is 20.5 N, what is the total force of friction on the student and skateboard? (e) Calculate the acceleration of the student and skateboard down the slope.

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.

Apersons beliefs and general outlook, which act like filters on the information they receive are called ?

To fully describe the photoelectric effect, scientists must consider which of the following to be quantized? o a. both light and matter o b. matter only o c. light only o d. neither light nor matter