It takes a force of 15 N to stretch an ideal spring of negligible mass 3.0 cm. The spring is placed on a frictionless horizontal tabletop with one end fixed. A small 50-g metal ball is placed at the free end.
By how much should the spring be compressed to set the ball
in motion horizontally at a speed of
4.5 m/s?
A) 21 cm
B) 4.5 cm
C) 2.1 cm
D) 9.0 cm
E) 4.2 cm

Starting with only the balmer series light (visible light), how could we ensure that the solar panels generate a current that mark can use for his power station? a)by gradually increasing the brightness (amount) of light that we shine on it. b)by gradually increasing the frequency of the light we shine on it. c)by gradually increasing the wavelength of the light that we shine on it.

Juan created a chart to him study for a test. which headings best complete the chart? x: transparent objects y: opaque objects x: opaque objects y: transparent objects x: high frequency waves y: low frequency waves x: low frequency waves y: high frequency waves

If a rock is thrown upward on the planet mars with a velocity of 12 m/s, its height (in meters) after t seconds is given by h = 12t − 1.86t2. (a) find the velocity of the rock after two seconds. m/s (b) find the velocity of the rock when t = a. 12−3.72a m/s (c) when will the rock hit the surface? (round your answer to one decimal place.) t = s (d) with what velocity will the rock hit the surface? m/s