Has a skateboard. your gonna have to give more details the. that just one .
You would want it to be greater than D. friction force
It needs be greater than the friction applied to it.
From Newton's second law of motion, it is identified that the net force applied to the object with mass m, will make it move with an acceleration of a. This can be mathematically translated as,
F = m x a
To solve for the mass of the sled, we derive the equation above such that,
m = F / a
Substituting,
m = (18 N) / (0.39 m/s²)
m = 46.15 kg
Then, we add to the calculated mass the mass of the extra material.
total mass = 46.15kg + 4.5 kg
total mass = 50.65 kg
We solve for the normal force of the surface to the object by calculating its weight.
F₂ = (50.65 kg)(9.8 m/s²)
F₂ = 496.41 N
The force that would allow barely a movement for the object is equal to the product of the normal force and the coefficient of kinetic friction.
F = (F₂)(c)
c = F/F₂
Substituting,
c = 18 N/496.41 N
c = 0.0362
<em>ANSWER: c = 0.0362</em>
Answer:
RL=100K → Vo=9.90 mV
RL=10K → Vo=9.09 mV
RL=1K → Vo=5 mV
RL=100 → Vo=909.09 μV
In order to obtain 80% of the power source we have to put a resistor of 4 KOhm.
Explanation:
Here we have a power source in serie with a resistor of 1K and RL, in order to obtain the Vo voltage we have to apply the voltage divider rule, that states:

Substituing the resistor values of RL we obtained the following results:
RL=100K → Vo=9.90 mV
RL=10K → Vo=9.09 mV
RL=1K → Vo=5 mV
RL=100 → Vo=909.09 μV
In order to find the lowest value that gives us 80% of the source voltage we have to use the voltage divider rule again and make the Vo equal to 0.8 Vin:

The result of the last equation is 4000, so in order to obtain 80% of the power source we have to put a resistor of 4 KOhm.
Explanation:
Distance travelled (d) = 56 metres
Time taken (t) = 7 seconds
velocity of the object (V)
= d / t
= 56 / 7
= 8 m/s
The velocity of the object is 8 m/s.
Hope it will help :)