Why is a control important in an experiment?

An electric circuit consists of a variable resistor connected to a source of constant potential difference. If the resistance of the resistor is doubled, then

The men's world record (as of 2007) for swimming 1500 m in a long course pool is 14 min 34.56 s. At this rate, how many seconds would it take the men's world record holder to swim 0.750 mi? (1 mi = 1609 m)

4. A 1.5 Kg pumpkin is dropped from a 2.5 meter high window on Halloween night. What is the pumpkin's speed right before it reaches the ground?

A block of mass 15.0 kg slides down a ramp inclined at 28.0∘ above the horizontal. As it slides, a kinetic friction force of 30.0 N parallel to the ramp acts on it. If the block slides for 5.

Four boxes of the same volume are each completely filled with one of the following items: sand, marbles, paperclips, or dice. The order of boxes from least to greatest mass is as follows: paperclips, dice, marbles, and sand.

What is the energy source that heats a contracting protostar?

What unit is kg divided by m/s^2

If the energy stored in the fully charged battery is used to lift the battery with 100-percent efficiency, what height is attained? Assume that the acceleration due to gravity is 9.8 m/s2m/s2 and is constant with height

How does the mass of an astronaut change when she travels from earth to the moon? how does her weight change?

If an object has a mass of 20 grams and a volume of 40 cm3, what is its density in g/cm3?