Answer:
7.875 ft/s
Explanation:
L = 15 ft
dx/dt = 3 ft/s
x = 9 ft
Let the top of ladder is coming down with the rate of dy/dt.
use Pythagorean theorem
L^2 = x^2 + y^2 .... (1)
Differentiate both sides with respect to t
0 = 2 x dx/dt + 2y dy/dt
x dx/dt = - y dy/dt
When, x = 9 ft then y = ? . Put this in equation (1)
15^2 = 9^2 + y^2
225 - 81 = y^2
y = 12 ft
So
dy/dt = - x (dx/dt) / y = - 9 (3) / 12 = - 9/4 ft/s
Let A be the area of the triangle
A = 1/2 (base)(height)
A = 1/2 (x y)
Differentiate both sides with respect to t
dA/dt = 0.5 (y dx/dt + x dy/dt)
dA/dt = 0.5 [ 12 (3) - 9 (9/4)]
dA/dt = 0.5(36 - 81 /4) = 31.5 / 4 = 7.875 ft/s
The energy from the sun that reaches the corn is about two billionths.
Answer:
A. A car can still be moving without acceleration when it has some velocity.
B. A car can come to a stop when moving itself when it has some de acceleration.
C.A ca can start at 0 m/s and speed up to 15 m/s when it has some acceleration.
Explanation:
A. since the car has no acceleration the velocity of the car would help it moving.
B. when the car is moving with some velocity but coming to a stop this is possible of and only if it has some de acceleration
C. since the speed of the car increases from 0 to 15 m/s acceleration is involved. If the speed was constant there would be no acceleration involved.
Answer:
Part a)
charge through the battery is
Part b)
Maximum current is
i = 386 A
Explanation:
Part a)
As we know that the rating of battery is given as
here we also know that the charge given by the battery is same as the capacity of the battery
so we will have
Part b)
Now we know that current in the wire is given by
now plug in all values in it
<h3>
Answer:</h3>
539.56 Joules
<h3>
Explanation:</h3>
- Efficiency of a machine is the ratio of work output to work input expressed as a percentage.
- Efficiency = (work output/work input) × 100%
- Efficiency of a machine is not 100% because so energy is lost due to friction of the moving parts and also as heat.
In this case;
Efficiency = 94%
Work input = 574 Joules
Therefore, Assuming work output is x
94% = (x/574 J) × 100%
0.94 = (x/574 J)
<h3>x = 539.56 J</h3>
Thus, you get work of 539.56 J from the machine