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3 years ago

What minimum speed must the rocket have just before impact in order to save the explorer's life?

1 answer:

34kurt3 years ago

8 0

<span>Answer: Assuming that I understand the geometry correctly, the combine package-rocket will move off the cliff with only a horizontal velocity component. The package will then fall under gravity traversing the height of the cliff (h) in a time T given by h = 0.5*g*T^2 However, the speed of the package-rocket system must be sufficient to cross the river in that time v2 = L/T Conservation of momentum says that m1*v1 = (m1 + m2)*v2 where m1 is the mass of the rocket, v1 is the speed of the rocket, m2 is the mass of the package, and v2 is the speed of the package-rocket system. Expressing v2 in terms of v1 v2 = m1*v1/(m1 + m2) and then expressing the time in terms of v1 T = (m1 + m2)*L/(m1*v1) substituting T in the first expression h = 0.5*g*(m1 + m2)^2*L^2/(m1*v1)^2 solving for v1, the speed before impact is given by v1 = sqrt(0.5*g/h)*(m1 + m2)*L/m1</span>

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Sometimes balance point may not be obtained on the potentiometer wire why

scoundrel [369]

Solution
Let a cell of emf E be connected across the entire length L of a potentiometer wire . Now , if the balance point is obtained at a length l during measurement of an unknown voltage

.
The balance point is not on the potentiometer wire - this statement means that

. In that case ,
l > L
V > E

8 0

2 years ago

A 74 kg firefighter slides, from rest, 4.9 m down a vertical pole. (a) If the firefighter holds onto the pole lightly, so that t

In-s [12.5K]

Answer:

Her speed is 9.8 meter per second

Explanation:

Newton's second law states that acceleration (a) is related with force (F) by:

$\sum\overrightarrow{F}=m\overrightarrow{a}$ (1)

Here the only force acting on the firefighter is the weight F=mg so (1) is:

$mg=ma$

Solving for a:

$a=g$

Now with the acceleration we can use the Galileo's kinematic equation:

$Vf^{2}=Vo^{2}+2a\varDelta x$ (2)

With Vf the final velocity, Vo the initial velocity and Δx the displacement, because the firefighter stars from rest Vo=0 so (2) is:

$Vf^{2}=2a\varDelta x$

Solving for Vf

$Vf=\sqrt{2g\varDelta x}=\sqrt{2(9.81)(4.9)}$

$Vf=9.8\frac{m}{s}$

6 0

2 years ago

Which of the following pieces of laboratory equipment is not directly used to make measurements

RoseWind [281]

I believe the answer is a test tube.

4 0

3 years ago

Read 2 more answers

How can the rate of a reaction be decreased?

andre [41]

Answer:

Option A

Lowering the amount of reactants

Explanation:

To reduce the rate of chemical reaction, one can reduce temperature or surface area. The addition of catalysts increases rate of reaction but decreasing the amount of reactants decreases rate of reaction. Therefore, from the choices provided, choice A is correct.

6 0

2 years ago

You see a marble sign. Its letters are too worn to read. What caused this?

enyata [817]

It is called weathering. there are three different types of weathering, physical weathering, chemical weathering, and biological weathering. Your particular question is caused by chemical weathering.

8 0

3 years ago