Question

a 75kg bicyclist is coasting (not pedaling) to the right while experiencing a 40n drag. neglect any friction impeding the motion.
how many forces are acting on the bicyclist?
what is the magnitude of the net force on the bicyclist?
what is the magnitude of her acceleration?
describe her speed:

Explanation:

Sub - question 1: How many forces are acting on the bicyclist?

To determine the number of forces, we analyze the forces acting on the bicyclist. The forces are: gravitational force (weight) acting downwards, normal force from the ground acting upwards, and drag force acting opposite to the direction of motion (left, since the bicyclist is moving right). So there are 3 forces.

Step 1: Analyze vertical and horizontal forces

In the vertical direction, the gravitational force ($F_g$) and the normal force ($F_N$) are equal in magnitude and opposite in direction, so their vector sum is zero. In the horizontal direction, the only force is the drag force ($F_d = 40N$) acting to the left (opposite to the motion). Since the vertical forces cancel out, the net force ($F_{net}$) is equal to the drag force in the horizontal direction.

Step 2: Calculate net force

$F_{net}=F_d = 40N$ (because vertical forces have a net force of 0)

Step 1: Recall Newton's second law

Newton's second law is given by $F = ma$, where $F$ is the net force, $m$ is the mass, and $a$ is the acceleration. We know the net force $F_{net}=40N$ and the mass $m = 75kg$.

Step 2: Solve for acceleration

Rearranging the formula for acceleration, we get $a=\frac{F_{net}}{m}$. Substituting the values, $a=\frac{40N}{75kg}\approx0.53m/s^{2}$

Answer:

3

Sub - question 2: What is the magnitude of the net force on the bicyclist?