Answer:
108,000 joules
Step-by-step explanation:
Kinetic energy, k = 1/2 mv^2
Where,
m = mass of the object in kilogram
v = velocity in meters per seconds
If
Velocity of an object = 20 meters per seconds
Kinetic energy = 48,000 joules
Solve for m
k = 1/2 mv^2
48,000 = 1/2 × m × 20^2
48,000 = 1/2 × m × 400
48,000 = 200m
m = 48,000 / 200
m = 240 kg
If it speeds up to 30 meters per second, then what is its new kinetic energy?
k = 1/2 mv^2
Using m = 240 kg
k = 1/2 mv^2
= 1/2 × 240 × 30^2
= 1/2 × 240 × 900
= 216,000 / 2
= 108,000 joules
The new kinetic energy = 108,000 joules
This can be solved in two ways: With heavy tools or with just algebra.
What is your level? Have you studied calculus?
With pure algebra:
We need to find the maximum of the function <span>h = −16t^2 + 36t + 5
Lets take out -1 for simplicity:
</span><span>h = −(16t2 - 36t - 5)
For now lets just work with this: </span>16t^2 - 36t - 5
16t^2=(4t)^2
(4t-x)^2= 16t^2-2*4xt+x^2
we have -36t so x should be 4.5 as 2*4*4.5=36
Lets see what we have now:
16t^2 - 36t - 5= (4t-4.5)^2 is this true? No but close
(4t-4.5)^2= 16t^2- 2*4*4.5t +4.5^2= 16t^2-36t+20.25
16t^2 - 36t - 5 and 16t^2-36t+20.25 nearl the same just take away 25.25 from the right hand side
Getting long, just stay with me:
16t^2 - 36t - 5= (4t-4.5)^2 - 25.25
h= -{(4t-4.5)^2 -25.25}
h=-(4t-4.5)^2 + 25.25
We want to find the maximum of this function. -(4t-4.5)^2 this bit is always negative or 0, so it maximum is when it is 0. Solve: 4t-4.5=0
t=1,125
s= 18
and,
t= 48
These values makes it correct.
40*7= 280
You would put 280 over 320
280
-----
320
Take off the zeros since they both have one.
28
---
32
28/32 is your answer.
If you need a simplified version your answer would be 7/8
2x-4=x^2-4
-4=x^2-2x-4 (start moving everything to one side)
x^2-2x=0 (the 4 cancel out)
x(x-2)=0 (factor out an x)
x=0 & x=2 (solved for x)
y=2x-4 (pick one of the equations)
y=2(0)-4 (plug in x)
y=-4
(0,-4)
y=2(2)-4 (plug in the second point)
y=0
(2,0)
The greatest possible value of s is 2. (2,0)
