S + A = 450
$4S + $6A = $2340
S + A = 450
-6(S + A = 450)
-6S +-6A = -2700
4S + 6A = 2340
-2S = -360
-2S/-2 = -360/-2
S = 180
S + A = 450
180+ A =450
180-180 + A = 450-180
A = 270
Check
$4S + $6A = $2340
$4(180) + $6(270) = $2340
$720 + $1620 = $2340
$2340 = $2340
1,49x^2 and 81^6 are perfect squares<span />
Answer:
Step-by-step explanation:
a) The work done is equivalent to the change in potential energy of the block. The force due to gravity in the direction down the ramp does the work.
ΔPE = mg(Δh) = (1.25 kg)(9.8 m/s²)(1.81 m·sin(55.3°) ≈ 18.23 J
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b) The kinetic energy of the block can be used to estimate the speed:
KE = ΔPE = 1/2mv²
v = √(2KE/m) = √(2(18.23 J)/(1.25 kg)) ≈ 5.4 m/s
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c) Steven has added kinetic energy to the block. So, the final kinetic energy it has will be ...
initial KE + ΔPE = final KE
final KE = (1/2)mv² + 18.23 J = (1/2)(1.25 kg)(2.0 m/s)² + 18.23 J
= 2.5 J + 18.23 J = 20.73 J
So, the final velocity will be ...
v = √(2(20.73)/1.25) ≈ 5.76 m/s
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<em>Comment on the question</em>
For those of you seeking to copy the answer to "which forces do non-zero work?" we observe that there is no list of forces in this question to choose from. The best we can say is that the operative force is the component of gravity that is parallel to the ramp surface.
Answer : 2x² - 7x - 30
Step-by-step explanation: Multiply the brackets out (first x * 2x then x * 5) (second -6 * 2x then -6 * 5) which will give you 2x² + 5x - 12x - 30. Take away 12 from 5 which gave you the negative 7.