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kow [346]
3 years ago
9

You throw a small rock straight up from the edge of a highway bridge that crosses a river. the rock passes you on its way down,

8.00 s after it was thrown. what is the speed of the rock just before it reaches the water 21.0 m below the point where the rock left your hand? ignore air resistance
Physics
1 answer:
maw [93]3 years ago
4 0
V^2=u^2 +2aS
U is found first by considering that first 8 secs and using v=u+at. {different v and u though}

V=-u+gt.
Magnitude of u = magnitude of v if there is no resistance ( because the conservation of energy says the k. E. must be the same when it passes you as when it left your hand).... up is negative here, down is positive.
V+v=gt
2v= g x 8
V=4xg.= the initial velocity for the next calculation
V^2=(4g)^2+(2xgx21)

So v can be calculated.

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Find the Acceleration of a car with the mass of 1200kg and a force of 11x10^3 N
larisa86 [58]

Answer:

<h2>9.17 m/s²</h2>

Explanation:

The acceleration of an object given it's mass and the force acting on it can be found by using the formula

a =  \frac{f}{m}  \\

f is the force

m is the mass

From the question we have

a =  \frac{11 \times  {10}^{3} }{1200}  \\  = 9.16666...

We have the final answer as

<h3>9.17 m/s²</h3>

Hope this helps you

7 0
2 years ago
A 35.2-g sample of an alloy at 93.0°C is placed into 219 g of water at 22.0°C in an insulated coffee cup. Assume that no heat is
Korvikt [17]

Answer:

Explanation:

mass of the alloy = 35.2 g

temperature t of the alloy = 93° C

heat loss by alloy = mc ( t₁ - t₂) where t₁ = 93 and t₂ = 31.1° C

heat loss by alloy = 2178.88 c where c is the specific heat capacity of the alloy

heat gained by water = m cw ( t₂ - t₁ ) where t₁ of water = 22° C and t₂ of water = 31.1° C

heat gained by water = 8338.294

heat gained = heat loss

2171.84 c =  8338.294

c specific heat capacity of the alloy = 8338.294 / 2178.88 = 3.83 J/g.K

7 0
3 years ago
Identify the method of thermal energy transfer at work in hot air balloons. Explain how thermal energy is transferred in this sc
yan [13]
Thermal energy in the form of fire is generated by the combustion of fuel. Due to the tendency of hot air to rise upward, the heat generated rises to fill the space of the balloon. One this space is full of trapped hot air, the heat's tendency to rise causes the hot air balloon to be lifted into the air. 
8 0
3 years ago
Read 2 more answers
What do you need to calculate the mechanical advantage of a block and tackle? A.resistance force
Degger [83]

I think D is the right answer

God Bless

5 0
3 years ago
Read 2 more answers
Given two objects of the same mass but of different sizes, which object has a greater density?
wolverine [178]

Given two objects of the same mass but of different sizes, the one that has a greater density is: a. the smaller object

Due to the density of an object is the relation that exist between the mass and the space that the object occupies, if we have two objects with the same mass the one that is going to have a greater density is the smaller object because it occupies less space with more mass.  

We can prove it using the density formula to solve the following exercise:

Two objects have a mass of  100 g, and their volume are 20 cm³ and 10 cm³ respectively, what is the density of each one?

The general formula of the density is:

d = m/v

Where:

  • d= density
  • m= mass
  • v= volume

Information about the problem:

  • m = 100 g
  • v1= 20 cm³
  • v2=10 cm³
  • d1=?
  • d2?

Applying the density  formula we get:

d = m/v

d1 = 100g/20 cm³

d1 = 5g/cm³

d2 = 100g/10 cm³

d2 = 10g/cm³

With the results we can confirm that the object that has the greater density is the smaller, because it has less volume.

<h3>What is density?</h3>

It is a physical quantity that expresses the ratio of the body mass to the volume it occupies.

Learn more about density in: brainly.com/question/1354972

#SPJ4

4 0
10 months ago
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