Help please choose the correct

1. The most suitable scale to represent a force 100N on a graph paper is:

a- 1 cm for 50N.

b- 1 cm for 1N.

c- 1 cm for 0.5N.

2. A karateka breaks a board with his hands. what is the most significant effects of this force?

a- Set the board in motion.

b- Modify the board's motion.

c- Deform the shape of the board.

An object is 10 cm from the mirror, its height is 1 cm and the focal length is 5 cm. what is the image height? (indicate the object orientation by including the + or - sign with the answer.) hi = cm +1 -1 +10 -10

What is the measure of a change in an objects velocity?

The ultracentrifuge is an important tool for separating and analyzing proteins. because of the enormous centripetal accelerations, the centrifuge must be carefully balanced, with each sample matched by a sample of identical mass on the opposite side. any difference in the masses of opposing samples creates a net force on the shaft of the rotor, potentially leading to a catastrophic failure of the apparatus. suppose a scientist makes a slight error in sample preparation and one sample has a mass 10 mg larger than the opposing sample. if the samples are 12 cm from the axis of the rotor and the ultracentrifuge spins at 70,000 rpm, what is the magnitude of the net force on the rotor due to the unbalanced samples? ( be thorough on your answer)