Brian is attempting to high jump over a crossbar set at 2.13 m (7.0 ft). At the instant of takeoff (when he is no longer in contact with the ground), his vertical velocity is 4.2 m/s and his center of gravity is 1.25 m high. What is Brian's vertical acceleration at the instant of takeoff?

What is the gravitational attraction between a dating couple whose centers of mass are 0.630 m apart if the boy weighs 715 n and the girl weighs 465 n?

The dipole moment of the water molecule (h2o) is 6.17x10^-30 c. m. consider a water molecule located at the origin whose dipole moment p points in the +x-direction. a chlorine ion ( of charge-1.60x10^-19c , is located at x=3.00x10^-9m . assume that is much larger than the separation d between the charges in the dipole, so that the approximate expression for the electric field along the dipole axis can be used. a) find the magnitude of the electric force that the water molecule exerts on the chlorine ion. b) what is the direction of the electric force. -x-direction or +x-direction c) is this force attractive or repulsive?

Frequency of electromagnetic waves that a radio station is assigned. what do you call this type of wave?