Brian is repairing an old alarm clock. He needs to replace a device that converts the electric energy into sound energy. Which of these devices should he use? A.
battery
B.
buzzer
C.
motor
D.
switch

Critical mass is the of material required to produce a chain reaction. a.) minimum amount b.) atomic mass c.) precise amount d.) maximum amount

If a rock is thrown upward on the planet mars with a velocity of 12 m/s, its height (in meters) after t seconds is given by h = 12t − 1.86t2. (a) find the velocity of the rock after two seconds. m/s (b) find the velocity of the rock when t = a. 12−3.72a m/s (c) when will the rock hit the surface? (round your answer to one decimal place.) t = s (d) with what velocity will the rock hit the surface? m/s

For the car in the picture ,in which direction is the normal force? -into the screen -down -out of the screen -up