Final answer:
To find the force Sabrina exerts to accelerate her bike, you calculate her acceleration (change in velocity over time) and then use Newton's second law (force equals mass times acceleration) to find that she exerts approximately 75.15 newtons.
Step-by-step explanation:
To calculate the force exerted by Sabrina on her bicycle to accelerate from rest to 5 m/s in 3 seconds, we can apply Newton's second law of motion, which states that force is equal to mass times acceleration (F = ma).
First, we need to calculate Sabrina's acceleration (a). Acceleration is defined as the change in velocity (Δv) over time (t), which can be calculated using the formula:
a = Δv / t
Since she accelerates from 0 m/s to 5 m/s in 3 seconds, her acceleration is:
a = (5 m/s - 0 m/s) / 3 s = 1.67 m/s²
Now that we have the acceleration, we can determine the force exerted using her mass (45 kg):
F = ma = 45 kg × 1.67 m/s² = 75.15 N
Therefore, the force Sabrina exerts to accelerate her bike is approximately 75.15 newtons (N).