Một dao động điều hòa theo phương trình :x=4cos(10πt+π/4)(cm) Vào thời điểm t=0 vật đang ở đâu và di chuyển theo chiều nào?Vật tốc bằng bao nhiêu?

If a tank filled with water contains a block and the height of the water above point a within the block is 0.8 meter, what is the pressure at point a?

(2) (a) you have a simple circuit that consists of only a battery (δvbat=1.5v) and two resistors with resistance r1=10ω and r2=5ω, connected in series with each other. what is the current running through the battery? (b) you re-arrange your circuit so now r2 is attached in parallel to r1 rather than in series. what is the current running through the battery? (c) you add an additional resistor r3=7ω on the same branch as r2. what is the current running through the battery? (d) what is the power dissipated in r3?

1. a camcorder has a power rating of 19 watts. if the output voltage from its battery is 7 volts, what current does it use?answer units 2. a 1.5m wire carries a 6 a current when a potential difference of 57 v is applied. what is the resistance of the wire? yourunits 3. a clothes dryer uses about 2 amps of current from a 240 volt line. how much power does it use? yourunits 4.