Question

1. a 2.0 kg otter starts from rest at the top of a muddy incline 85 cm long and slides down to the bottom in 0.50 s. what net force acts on the otter along the incline?

Explanation:

Step1: Identify the kinematic - equation

The block starts from rest ($u = 0$), the displacement $s=85\ cm = 0.85\ m$ and time $t = 0.50\ s$. We use the equation $s=ut+\frac{1}{2}at^{2}$. Since $u = 0$, the equation simplifies to $s=\frac{1}{2}at^{2}$.

Step2: Solve for acceleration $a$

Rearranging the equation $s=\frac{1}{2}at^{2}$ for $a$, we get $a=\frac{2s}{t^{2}}$. Substituting $s = 0.85\ m$ and $t = 0.50\ s$ into the formula, we have $a=\frac{2\times0.85}{(0.50)^{2}}=\frac{1.7}{0.25}=6.8\ m/s^{2}$.

Step3: Use Newton's second - law

According to Newton's second - law $F = ma$, where $m = 2.0\ kg$ and $a = 6.8\ m/s^{2}$. Substituting the values, we get $F=2.0\times6.8 = 13.6\ N$.

Answer:

$13.6\ N$