Answer:
22.2 W
Explanation:
First of all, we calculate the work done by moving the wagon, using the formula:

where
F = 20 N is the magnitude of the force
d = 1000 m is the displacement of the wagon
is the angle between the direction of the force and of the displacement (assuming the force is applied in the direction of motion)
Substituting, we find

Now we can find the power generated, which is equal to the ratio between the work done and the time taken:

where
W = 20,000 J
t = 15 min = 900 s
Substituting,

And the same value in Joules/second (remember that 1 Watt = 1 Joule/second)
Answer:
W = 1418.9 J = 1.418 KJ
Explanation:
In order to find the work done by the pull force applied by Karla, we need to can use the formula of work done. This formula tells us that work done on a body is the product of the distance covered by the object with the component of force applied in the direction of that displacement:
W = F.d
W = Fd Cosθ
where,
W = Work Done = ?
F = Force = 151 N
d = distance covered = 10 m
θ = Angle with horizontal = 20°
Therefore,
W = (151 N)(10 m) Cos 20°
<u>W = 1418.9 J = 1.418 KJ</u>
Explanation:
It is given that,
Total mass is 70 kg
The truck exerts a constant force of 20 N.
Then the net force is given by :
F = ma
a is acceleration of rider

Initial velocity of rider is 0. So, using equation of kinematics to find the final velocity as :

Since, 1 m/s = 2.23 mph
4.28 m/s = 9.57 mph
So, the speed of the rider is 4.28 m/s or 9.57 mph.
Answer:
The current is halved
Explanation:
The relationship between the current and the resistance is given by Ohm's Law, as follows:

where,
V = Voltage
I = Current
R = Resistance
Therefore, if we double the resistance:

Hence the correct option is:
<u>The current is halved</u>
Answer:
Acids break down fabrics and can cause burns if the acids are strong.
Explanation:
A protective apron or lab coat is important when working with acids because acids break down fabrics and can cause burns if the acids are strong.
- An acid is a substance that interacts with water to produce excess hydroxonium ions in an aqueous solution.
- A strong acid ionizes completely in solution.
- When they come in contact with a fabric, they break them down violently.
- So, if they come in contact with the skin, it causes a violent break down of body tissues.
- The apron acts a protective layer.