"an ice skater applies a horizontal force to a
20.-kilogram block on frictionless, level ice,
causing the block to accelerate uniformly at
1.4 meters per second2 to the right. after the
skater stops pushing the block, it slides onto a
region of ice that is covered with a thin layer
of sand. the coefficient of kinetic friction
between the block and the sand-covered ice is
0.28.

calculate the magnitude of the force of friction
acting on the block as it slides over the
sand-covered ice. [show all work, including the
equation and substitution with units.]

An insurance company wants to know if the average speed at which men drive cars is higher than that of women drivers. the company took a random sample of 27 cars driven by men on a highway and found the mean speed to be 72 miles per hour with a standard deviation of 2.2 miles per hour. another sample of 18 cars driven by women on the same highway gave a mean speed of 68 miles per hour with a standard deviation of 2.5 miles per hour. assume that the speeds at which all men and all women drive cars on this highway are both approximately normally distributed with unknown and unequal population standard deviations.

Which of the following is not a part of the respiratory system? a. pharynx b. trachea c. pancreas d. larynx

The image below shows numerous volcanic mountains in the pacific northwest. what is the most likely cause of the volcanic and earthquake activity in this region?