An object is placed 13 cm from a concave spherical mirror of radius 9.0 cm. What type of image forms, and at what distance from the mirror? A. virtual image, 6.9 cm from the mirror
B. real image, 6.9 cm from the mirror
C. real image, 29 cm from the mirror
D. virtual image, 4.0 cm from the mirror

Which type of energy would have nothing to do with ironing clothes? a. heat b. chemical c. electrical d. mechanical

Engines for propeller-driven aircraft are limited in their maximum rotational speed by the fact that the tip speed of the propeller must not approach the speed of sound in air (mach i). taking 6 ft as a typical diameter for a propeller of a light airplane and 1100 fils as the speed of sound, find the upper limit on the rpm (revolutions per minute) of the propeller shaft.

A50 kg student climbs 3 m to the top of a set of stairs. calculate the change in the student’s gravitational potential energy from the bottom to the top of the stairs. show your calculations and include units in your answer. how much total work does the student do while climbing the stairs? show your calculations or explain your reasoning. include units in your answer. it takes the student 30 s to climb to the top of the stairs. what is the average power generated by the student climbing the stairs? show your calculations and include units in your answer. the next day the student carries a 10 kg backpack up the same stairs and again takes 30 s to reach the top of the stairs. is the average power you calculated in part (c) greater than, less than, or equal to the average power the student generated the next day? explain your answer.