Explanation:
The work done equals the change in energy.
W = ΔKE
W = 0 − ½mv²
W = -½ (0.270 kg) (-7.50 m/s)²
W = -7.59 J
Work is force times displacement.
W = Fd
-7.59 J = F (-0.150 m)
F = 50.6 N
Answer:
a) 
b) 
c) 
Explanation:
From the exercise we know that the ball strikes the building 16m away and its final height is 8m more than the initial
Being said that, we can calculate the initial velocity of the ball
a) First we analyze its horizontal motion


(1)
That would be our first equation
Now, we need to analyze its vertical motion


Knowing
in our first equation (1)


Solving for t

So, the ball takes to seconds to get to the other building. Now we can calculate its <u>initial velocity</u>

b) To find the <u>magnitude of the ball just before it strikes the building</u> we need to calculate its x and y components


So, the magnitude of the velocity is:

c) The <u><em>direction of the ball</em></u> is:

The volume of the room is the product of its dimensions:

Now, from the equation

where d is the density, m is the mass and V is the volume, we deduce

So, multiply the density and the volume to get the mass of air in the room.
Answer:
3349J/kgC
Explanation:
Questions like these are properly handled having this fact in mind;
Quantity of heat = mcΔ∅
m = mass of subatance
c = specific heat capacity
Δ∅ = change in temperature
m₁c₁(∅₂-∅₁) = m₂c₂(∅₁-∅₃)
m₁ = mass of block = 500g = 0.5kg
c₁ = specific heat capacity of unknown substance
∅₂ = block initial temperature = 50oC
∅₁ = equilibrium temperature of block and water after mix= 25oC
m₂= mass of water = 2kg
c₂ = specific heat capacity of water = 4186J/kg C
∅₃ = intial temperature of water = 20oC
0.5c₁(50-25) = 2 x 4186(25-20)
And we can find c₁ which is the unknown specific heat capacity
c₁ =
= 3348.8J/kg C≅ 3349J/kg C