Answer to Question #284477 in Physics for Fruit

Question

1.) How much impulse does a 10 N force produce if it is applied in 0.05s?

2.) A 0.80kg object at rest is given a force of 4.0N during a time interval of 2.0s What is the velocity of the object at the end of this time interval ?

3.) A 5.0kg ball rolls into a pillow at 2.0 m/s and stops in 5.0s, what is the average force exerted on the pillow?

4.) A 1500kg car moving east speeds up uniformly from 5.0 m/s to 30m/s in 8.0s. What constant force acts on the car

5.) How long must a 1500N force act on a 50kg cart to increase its speed from 50 m/s to 150 m/s

6.) A 300g ball moving at 20 m/s is hit by a bat. After the impact, the ball rebounds at the same speed along the same line. What was the impulse exerted by the bat on the ball?

Answer 1

1)

$$J=F\Delta t=10\ N\times0.05\ s=0.5\ N\times s.$$

2)

$$F\Delta t=\Delta p = m(v_f-v_i)=mv_f,$$ $$v_f=\dfrac{F\Delta t}{m}=\dfrac{4\ N\times2\ s}{0.80\ kg}=10\ \dfrac{m}{s}.$$

3)

$$F\Delta t=\Delta p = m(v_f-v_i),$$ $$F=\dfrac{m(v_f-v_i)}{\Delta t}=\dfrac{5\ kg\times(0-2\ \dfrac{m}{s})}{5\ s}=-2\ N.$$

4)

$$F=\dfrac{m(v_f-v_i)}{\Delta t}=\dfrac{1500\ kg\times(30\ \dfrac{m}{s}-5\ \dfrac{m}{s})}{8\ s}=4688\ N.$$

5)

$$\Delta t=\dfrac{m(v_f-v_i)}{F}=\dfrac{50\ kg\times(150\ \dfrac{m}{s}-50\ \dfrac{m}{s})}{1500\ N}=3.33\ s.$$

6)

$$J=m(v_f-v_i)=0.3\ kg\times(20\ \dfrac{m}{s}-(-20\ \dfrac{m}{s}))=12\ N\times s.$$