The angle a vector makes with the x-axis of a coordinate system must be what size in order to make one or more of its components negative?

A change in color during a reaction is often a sign that a chemical change has occurred.

Relative to the ground below, how many joules of Potential Energy does a 1000-kg boulder have at the top of a 5-m ledge?

This is the rate of flow electricity

A sample of the material halite measures 3.18 cm long by 3.06 cm wide by 2.79 cm high and has a mass of 58.75 g. What is the its specific gravity?

An automobile can be considered to be mounted on four identical springs as far as vertical oscillations are concerned. The springs of a certain car are adjusted so that the oscillations have a frequency of 4.42 Hz.

How many hops does a kangoroo do in 1 day

What are the average velocity and average acceleration of the tip of a 2.4 cm long hour hand of a clock?

What is the number one and most important rule to remember in soccer?

Why are convection currents; why are they hotter and colder parts of earth

A swimmer is swimming to the left with a speed of 1.0 m/s when she starts to speed up with constant acceleration. The swimmer reaches a final speed of 2.5 m/s over a distance of 5.0 m. How long did the swimmer take to speed up to 2.