An iron needle has been given a positive charge. Which type(s) of fields will exert a force on the needle? A only a magnetic field
B only a magnetic and an electrical field
C only an electrical and a gravitational field
D a magnetic, an electrical and a gravitational field ​

An object thrown vertically upward from the surface of a celestial body at a velocity of 36 m/s reaches a height of sequalsminus0.9tsquaredplus36t meters in t seconds. a. determine the velocity v of the object after t seconds. b. when does the object reach its highest point? c. what is the height of the object at the highest point? d. when does the object strike the ground? e. with what velocity does the object strike the ground? f. on what intervals is the speed increasing?

Find the momentum for a 2.6-kg brick parachuting straight downward at a constant speed of 8.4 m/s .

What is a good example of instantaneous speed