The resistivity of a metal increases slightly with increased temperature. This can be expressed as rho= rho0[1+α(T−T0)] , where T0 is a reference temperature, usually 20°C, and α is the temperature coefficient of resistivity. For copper, α = 3.9× 10−3 ° C−1. Suppose a long, thin copper wire has a resistance of 0.25 Ω at 20°C.

At what temperature, in °C, will its resistance be 0.31 Ω?

In raising a 6200-n piano with a pulley system, the movers note that, for every 2.2 m of rope pulled down, the piano rises 0.12 m . ideally, find the force required to lift the piano.

Imagine that you have two balloons (or, better yet, actually inflate two balloons, if possible). create static electricity around one of the balloons by rubbing it against your hair or your sweater and then bring that balloon close to the other balloon, which has not been charged. try this with at least one other object—and for variety in the discussion, avoid using an object already described by your classmates. then, for your initial post to the discussion, answer the following questions: what happened with the two balloons?

While the change in blank will remain the same during a collision, the force needed to bring an object to a stop can be blank if the time if collision is blank