In the diagram, a force of 20 newtons is applied to a block. the block is in dynamic equilibrium. what is the magnitude and direction of the frictional force
a. 20 newtons in the direction of the applied force
b .20 newtons opposite to the direction of the applied force
c. 20 newtons perpendicular to the direction of the applied force
d. 20 newtons in two directions, perpendicular and in the direction of the applied force
e. no friction is acting on the block.

Give one example to show that when substances are mixed,it may result in a chemical or a physical change depending on the conditions.

What is the increase in density of a medium due to wave travel?

Two horses begin at rest. after a few seconds, horse a is traveling with a velocity of 10 m/s west, while horse b is traveling with a velocity of 13 m/s west. which horse had a greater acceleration? a. horse a because its change in velocity was greater than horse b's in the same time. b. horse b because its change in velocity was greater than horse a's in the same time. c. horse b because its change in velocity was the same as horse a's, but it took less time. d. both horses had the same acceleration.