A2.5g copper penny is given a charge of -4.0*10^-9c. how mny excess electrons are on the penny?

•• al and bert are jogging side-by-side on a trail in the woods at a speed of 0.75 m/s. suddenly al sees the end of the trail 35 m ahead and decides to speed up to reach it. he accelerates at a constant rate of 0.50 m/s2, while bert continues on at a constant speed. (a) how long does it take al to reach the end of the trail? (b) once he reaches the end of the trail, he immediately turns around and heads back along the trail with a constant speed of 0.85 m/s. how long does it take him to meet up with bert? (c) how far are they from the end of the trail when they meet?

A4.0-cm tall light bulb is placed a distance of 32.0 cm from a concave mirror having a focal length of 16.0 cm. determine the image distance

A51 kg woman skis down a hill and her kinetic energy is 9.96e4 j. what is her speed?