Question

You are part of a searchand- rescue mission that has been called out to look for a lost explorer. You’ve found the missing explorer, but you're separated from him by a 200- m -high cliff and a 30- m -wide raging river. To save his life, you need to get a 5.6 kg package of emergency supplies across the river. Unfortunately, you can't throw the package hard enough to make it across. Fortunately, you happen to have a 0.70 kg rocket intended for launching flares. Improvising quickly, you attach a sharpened stick to the front of the rocket, so that it will impale itself into the package of supplies, then fire the rocket at ground level toward the supplies. What minimum speed must the rocket have just before impact in order to save the explorer’s life?

Answer 1

Answer:

$v_r = 42.3 m/s$

Explanation:

As we know that the width of the river is given as

$w = 30 m$

now the height is given as

$h = 200 m$

now by kinematics we have

$h = \frac{1}{2}gt^2$

$200 = \frac{1}[2}(9.81)t^2$

$t = 6.38 s$

now the speed required to cross the river is given as

$v = \frac{w}{t}$

$v = \frac{30}{6.38}$

$v = 4.7 m/s$

now we can use momentum conservation to find the speed of rocket just before collision

$m_r v_r = (m_r + m) v$

$0.70(v_r) = (5.6 + 0.70)(4.7)$

$v_r = 42.3 m/s$

Answer 2

Answer:

a searched rescue misson 400-m

Explanation: