When a hammer strikes a nail, the nail A. exerts balanced forces that helps it from moving
B. exerts balanced forces that helps it from moving
C. exerts an unbalanced force that changes its velocity.
D. exerts an equal and opposite force back on the hammer.

Clara is shopping in a grocery store with her friend. each has their own shopping cart in which they want to place their items. the shopping carts are identical. clara and her friend add the same type and number of items to each of their carts. in the baking aisle, however, clara adds 20 pounds of sugar to her own cart, and her friend adds only 10 pounds of sugar to her own cart. which of the following statements best explains what clara must do to accelerate at the same rate as her friend? a. she must add more sugar to her cart. b. she must apply more force to move her cart. c. she must add 20 pounds of salt instead of 20 pounds of sugar to her cart. d. she must apply less force to move her cart.