Question

28 if the impulse delivered to an object is 25 n.s. assume that the object has a force of 50 n acting on it. the time of the during which the impulse was delivered is (a) 2.0 s (b) 0.5 s (c) 500 s (d) 1250 s 29. an ostrich egg of mass m is thrown at a speed v into a sagging bedsheet and is brought to rest in time t. the average force of egg impact is $\frac{mv}{t}$. if the mass of the egg is 2.0 kg, its speed when it hits the sheet is 3.0 m/s, and it is brought to rest in 0.5 s. the average force that acts is (a) 12 n (b) 6 n (c) 1 n (d) 1.5 n (f) none of the above

Explanation:

Step1: Recall impulse - force formula

The formula for impulse $J$ is $J = F\times t$, where $J$ is impulse, $F$ is force and $t$ is time.

Step2: Solve for time in the first problem

Given $J = 25\ N\cdot s$ and $F=50\ N$. Rearranging the formula $t=\frac{J}{F}$. Substitute the values: $t=\frac{25\ N\cdot s}{50\ N}= 0.5\ s$.

Step3: Solve for force in the second problem

The formula for average force $F_{avg}=\frac{mv}{t}$. Given $m = 2.0\ kg$, $v = 3.0\ m/s$ and $t=0.5\ s$. Substitute the values: $F_{avg}=\frac{2.0\ kg\times3.0\ m/s}{0.5\ s}=\frac{6\ kg\cdot m/s}{0.5\ s}=12\ N$.

Answer:

1. (b) 0.5 s
2. (a) 12 N