When a piece of wood is distorted by a karate chop, the top of the board is

compressed while the bottom is stretched as shown. Therefore, you must first

consider the change in length of the bottom of the board where the break

begins. Chantal is a black belt in karate and she breaks a 30.0-cm piece of

wood with a force of 70.0 N, changing it in length by 4.0 104 cm. What is

the cross-sectional area of the piece of wood? (Ywood 1.0 109 N/m2)

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.

(**i would really appreciate if this was answered soon** ) which pair of quantities includes one quantity that increases as the other decreases during simple harmonic motion?

An alien spaceship is 500 m above the ground and moving at a constant velocity of 150 m/s upwards. how high above the ground is the ship after 5 seconds?