Answer:
μ = 0.37
Explanation:
For this exercise we must use the translational and rotational equilibrium equations.
We set our reference system at the highest point of the ladder where it touches the vertical wall. We assume that counterclockwise rotation is positive
let's write the rotational equilibrium
W₁ x/2 + W₂ x₂ - fr y = 0
where W₁ is the weight of the mass ladder m₁ = 30kg, W₂ is the weight of the man 700 N, let's use trigonometry to find the distances
cos 60 = x / L
where L is the length of the ladder
x = L cos 60
sin 60 = y / L
y = L sin60
the horizontal distance of man is
cos 60 = x2 / 7.0
x2 = 7 cos 60
we substitute
m₁ g L cos 60/2 + W₂ 7 cos 60 - fr L sin60 = 0
fr = (m1 g L cos 60/2 + W2 7 cos 60) / L sin 60
let's calculate
fr = (30 9.8 10 cos 60 2 + 700 7 cos 60) / (10 sin 60)
fr = (735 + 2450) / 8.66
fr = 367.78 N
the friction force has the expression
fr = μ N
write the translational equilibrium equation
N - W₁ -W₂ = 0
N = m₁ g + W₂
N = 30 9.8 + 700
N = 994 N
we clear the friction force from the eucacion
μ = fr / N
μ = 367.78 / 994
μ = 0.37
Answer: #4
Sally is faster.
Explanation:
If you multiply Sallies it is going to be less than Jessica's.
Answer:
Explanation:
Givens
d = 8.5 meters
vi = 0
a = 9.81
t = ?
Formula
d = vi * t + 1/2 a t^2
Solution
8.5 = 0 + 1/2 9.81 * t^2 multiply both sides by 2
8.5 = 4.095 t^2 Divide both sides by 4.095
8.5/4.095 = t^2
1.7329 = t^2 Take the square root of both sides
t = 1.316
It takes 1.316 seconds to hit the ground.
Equivalent resistance is also known as the overall resistance.
For resistors in a series circuit, the total resistance is computed using the formula:

In other words, you just add up the resistance of each resistor in the series circuit. In your case you only have two resistors. You have 2Ω and 4Ω. So all you need to do is add that up.


The total resistance of the series circuit is 6Ω
In a parallel circuit you get the total resistance using the formula:

First you get the sum of all fractions and at the end take the reciprocal of the resulting fraction and divide. So let us take your problem into consideration where you have two resistors that have a resistance of 2Ω and 4Ω.




Get the reciprocal of the resulting fraction 3/4 and then divide. The reciprocal of 3/4 is 4/3.
4/3 = 1. 33Ω
So if you compare the equivalent resistance of the two circuits, the series circuit has a higher equivalent resistance.
Answer:
(a) 
(b) 
(c) 44133.5 m
Explanation:
<u>Given:</u>
= initial speed of the rocket in the first stage = 0 m/s
= final speed of the rocket in the first stage
= final speed of the rocket in the second stage
= time interval of the first stage
= time interval of the second stage
= distance traveled by the rocket in the first stage
= distance traveled by the rocket in the second stage
= distance traveled by the rocket in whole time interval
Part (a):
Since the rocket travels at constant acceleration.

Hence, the expression of the rocket's speed at time
.
Part (b):
In this part also, the rocket moves with a constant acceleration motion.

Hence, the expression of the rocket's speed in the time interval
is
.
Part (c):
For the constant acceleration of rocket, let us first calculate the distance traveled by the rocket in both the time intervals.

Similarly,

Hence, the rocket moves a total distance of 44133.5 m until the end of the second period of acceleration.