A dancer moves in one dimension back and forth across the stage. If the end of the stage nearest to her is considered to be the origin of an x axis that runs parallel to the stage, her position, as a function of time, is given by X(t) = [(0.11 m/s^3)t3^- (0.55 m/s^2)t^2 + (1.70 m/s)t - 4.50 m]i. Find an expression for the dancer's velocity as a function of time. (Assume SI units. Do not include units in your answer. Use the following as necessary: t.) v(t) = i

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? question 2 options: the balloons rise at the same rate. both balloons are the same size. the ballons both rise. the cold ballon is larger than the warm balloon. the cold balloon expands and rises. the warm balloon shrinks and sinks. the warm balloon expands and rises. the cold balloon shrinks and sinks.

Gordon is going for a run through the park, but it is cold outside. the low outside temperature could affect his personal safety.

What is the mass of the water that is being heated? it requires 2,500 joules to raise a certain amount of water (c = 4.186 jig c) from 20.0°c to 60.0°c. o 159 o 40 g o 63 g o 80 g