A 0.057 kg tennis ball and a tennis racket collide. The racket has an initial momentum of -2.80 kg•m/s and a final momentum of -1.97 kg•m/s. The ball has an initial momentum of 0.02565 kg•m/s. If you assume the collision is elastic, what is the final velocity of the ball? A. -4.75 m/s
B. -83.27 m/s
C. -0.80 m/s
D. -14.11 m/s
(The picture is my notes that I don't understand) :/ Please help

This chart shows characteristics of three different types of waves. which statement is best supported by the information in the chart? wave x and wave y are mechanical waves, and wave z is an electromagnetic wave. wave x and wave y are electromagnetic waves, and wave z is a mechanical wave. wave x and wave z are electromagnetic waves, and wave y is a mechanical wave. wave x and wave z are mechanical waves, and wave y is an electromagnetic wave.

The heater element of a 120 v toaster is a 5.4 m length of nichrome wire, whose diameter is 0.48 mm. the resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10-6 ω·m. the toaster is operated at a voltage of 120 v. (a) what is the power drawn by the toaster? (b) if the cost of electricity is 12 ¢ per kilowatt-hour, and it takes 2 minutes to toast bread, how much does it cost for toasted bread? (c) when the heater element is at room temperature, is the resistivity in the nichrome wire greater than, less than, or equal to it’s resistivity when at operating temperature? explain.

Which radioisotope is used in dating geological formations?