Question

select the correct answer. gina is driving her car to work, but shes stopped at a red light. when the light turns green, she presses the gas pedal and accelerates (speeds up) to move the car. which of these statements is true the moment gina presses the gas pedal? assume the road is flat and level. a. the net force on the car is zero in the horizontal direction. b. the net force on the car is zero in the horizontal and the vertical directions. c. the net force on the car is greater than zero in the horizontal direction. d. the net force on the car is greater than zero in the vertical direction. e. the net force on the car is less than zero in the vertical direction.

Explanation:

Step1: Recall Newton's second law

According to Newton's second law $F = ma$, where $F$ is the net - force, $m$ is the mass and $a$ is the acceleration.

Step2: Analyze the vertical forces

In the vertical direction, the weight of the car $mg$ acts downwards and the normal force $N$ from the road acts upwards. Since the road is flat and level and the car is not moving vertically, $N - mg=0$, so the net - force in the vertical direction is zero.

Step3: Analyze the horizontal forces

When Gina presses the gas pedal, the car starts to accelerate (speed up) in the horizontal direction. According to Newton's second law, if there is an acceleration $a_x$ in the horizontal direction and mass $m$ of the car is non - zero, then the net force $F_x=ma_x>0$ in the horizontal direction.

Answer:

C. The net force on the car is greater than zero in the horizontal direction.