Physics questions

br fall starting from rest fall starting with an upward speed of 20 m /s fall starting with a downward speed of 20 m /s remain stationary there is no net horizontal force acting on a ball the reference system to the car is noninertial there is net force in the forward direction the force in the forward direction is cancelled by the inertial force There is not horizontal A force acts backward A force acts forward There is a centrifugal force zero 80 Lbs 160

Lbs 240 Lbs the plane of pendulum rotates the sun rises and sets each day hurricanes turn counterclockwise in the Northern Hemisphere clockwise in the Southern The stars exhibit parallax 50 of c 75 of c equal to c 150 of c the one at the front the one at the back they exploded simultaneously the answer depends on the speed of the skateboard shorter than longer than still The answer depends on the speed of the object Mercury Earth The acceleration are the same Neither team can determine their acceleration at the same rate slower faster

Extra Credit Lab

For this one , you need a balloon and a pitcher or some other container It 's easiest if the container is transparent enough to see the level of water in it from the outside

1 ) Inflate the balloon to a point where it will fit completely inside the pitcher , but with some place around it and below it . Don 't inflate it fully : it should be able to expand

2 ) Slowly fill the pitcher with cold top water , holding balloon down until the pitcher overflows . Hold balloon completely submerged for a couple of minutes , adding more water if necessary to keep the pitcher full . Remove balloon and mark the level of the water

Repeat 2 using warm or tolerably hot water . Is the water level after removing of the balloon the same in both cases ? Why Answer

The water level will be different in the two cases

The level was lower with hot water than that with cold water

This is because , cold water causes shrinkage of the gases in the balloon , and therefore , shrinkage of the balloon thus more space is there between the balloon and the pitcher and hence more water is accommodated in the pitcher

In case of hot water expansion of the balloon takes place , which takes the remaining space between the pitcher and the balloon and therefore less water is accommodated in the pitcher...