1. Một khối trụ đặc đồng chất, khối lượng m= 0,5kg bán kính R bắt đầu lăn không trượt từ đỉnh một mặt phẳng nghiêng dài 2m, góc nghiêng α. Biết vận tốc dài của tâm trụ đặc khi lăn đến chân mặt phẳng nghiêng là v=2spr2 m/s, mômen quán tính của khối trụ I=mR^2/2 /2. Hãy tính:
a, Gia tốc của tâm khối trụ và góc nghiêng α.
b, Công và công suất trung bình của trọng lực trong quá trình chuyển động

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.

John throws .4 kg ball with velocity of 18 m/s. hits .2 kg bottle and bottle flies 25 m/s. how fast is ball traveling after hitting the bottle?

If element x has 99 protons how many electrons does it have