Explanation :
It is given that, a heavy box is in the back of a truck and the truck is accelerating to the right.
The description is shown in<em> figure 1</em>. Here, the forces that act on both box and the truck are the normal force, the frictional force and their weight mg.
The free body diagram is shown in <em>figure 2</em>. This shows the total forces ( F = ma )acting on the truck. As a result, the truck will move in a forward direction.
Hence, this is the required explanation.
The force between two parallel wires carrying currents in the same direction is attractive. It is repulsive if the currents are in opposite directions.
The minimum power is 490 W
Explanation:
The work that needs to be done by the robot in order to climb the shelves is equal to the gain in gravitational potential energy of the robot + object, therefore:
where
m = 15 kg + 5 kg = 20 kg is the total mass of the system
is the acceleration of gravity
is the change in height
Substituting,
Now we can calcualte the power (wattage) that the robot must have, using the equation
where
W = 3,920 J is the work done
t = 8 s is the time interval
Substituting,
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Answer:
help me, I'll help you? please
Do you remember the general equation for the distance covered
by a moving object ? There are not many perfect opportunities to
use it in all its glory, but I think this is one of them.
Position =
(starting distance) + (starting speed) (time) + (1/2) (acceleration) (time)²
H = starting position + (starting speed x t) + 1/2 A t²
Here's how we can use it, with some careful definitions:
-- Let's say the surface of the sea is zero height.
Then 'H' ... the position at the end ... is zero, when it plunks into the water, and
the starting, original position of the stone is +10 on the cliff in the man's hand.
-- Starting speed is +5 ... 5 m/s upward, when he tosses it.
-- Acceleration is 9.8 m/s² downward ... the acceleration of gravity.
I think this is going to work out just beautifully !
0 = (5) + 5t - 1/2 (9.8) t²
-4.9 t² + 5t + 5 = 0 That's the whole thing right there. Look how gorgeous that is !
Solve it for 't' with the quadratic equation,
A = -4.9
B = 5
C = 5
When you solve a quadratic with the formula, you always get two roots.
If it's a real-world situation, one of them might not make sense. That's
the result in this case.
The two roots are
t = - 0.622 second
and
t = + 1.642 second
The first one isn't useful, because it means 0.622 second <u>before</u> the man
tossed the stone up.
So our answer is: We hear the 'plunk' <em>1.642 second</em> after the upward toss.
