A concave mirror with a focal length of 20.0 cm is used to observe the image of a 1.75 cm tall candle. The candle is placed 15.0 cm in front of the mirror. The image is
A. inverted, 7.00 cm tall, and located 60.0 cm from the mirror
B. inverted, 0.438 cm tall, and located 60.0 cm from the mirror
C. erect, 7.00 cm tall, and located 60.0 cm from the mirror
D. impossible to see

Awheel rotates without friction about a stationary horizontal axis at the center of the wheel. a constant tangential force equal to 82.0 n is applied to the rim of the wheel. the wheel has radius 0.150 m . starting from rest, the wheel has an angular speed of 12.8 rev/s after 3.88 s. what is the moment of inertia of the wheel?

Consider an ordinary, helium-filled party balloon with a volume of 2.2 ft3. the lifting force on the balloon due to the outside air is the net resultant of the pressure distribution exerted on the exterior surface of the balloon. using this fact, we can derive archimedes’ principle, namely that the upward force on the balloon is equal to the weight of the air displaced by the balloon. assuming that the balloon is at sea level, where the air density is 0.002377 slug/ft3, calculate the maximum weight that can be lifted by the balloon. note: the molecular weight of air is 28.8 and that of helium is 4.

Due in 40 explain in terms of frame of reference if you’re inside a moving train everything on the outside can seem to be moving