I need help with the circled one

You are the juror of a case involving a drunken driver whose 1041 kg sports car ran into a stationary 1928 kg station wagon stop

mina [271]

1. Find the force of friction between the sports car and the station wagon stuck together and the road. The total mass m = 1928kg + 1041kg = 2969kg. The only force in the x-direction is friction: F = μ*N = μ * m * g
2. Find the acceleration due to friction:
F = m*a = μ * m * g => a = μ * g = 0.6 * 9.81
3. Find the time it took the two cars stuck together to slide 12m:
x = 0.5*a*t²
t = sqrt(2*x / a) = sqrt(2 * x / (μ * g) )
4. Find the initial velocity of the two cars:
v = a*t = μ * g * sqrt(2 * x / (μ * g) ) = sqrt( 2 * x * μ * g)
5. Use the initial velocity of the two cars combined to find the velocity of the sports car. Momentum must be conserved:

m₁ mass of sports car
v₁ velocity of sports car before the crash
m₂ mass of station wagon
v₂ velocity of station wagon before the crash = 0
v velocity after the crash

m₁*v₁ + m₂*v₂ = (m₁+m₂) * v = m₁*v₁
v₁ = (m₁+m₂) * v / m₁ = (m₁+m₂) * sqrt( 2 * x * μ * g) / m₁
v₁ = 33.9 m/s

7 0

3 years ago

What is the voltage output (in V) of a transformer used for rechargeable flashlight batteries, if its primary has 475 turns, its

VMariaS [17]

Answer:

Output voltage is 1.92 volts.

Explanation:

Given that,

Number of turns in primary coil, $N_p=475$

Number of turns in secondary coil, $N_s=8$

Input voltage, $V_i=114\ V$

We need to find the voltage output of a transformer used for rechargeable flashlight batteries. For a transformer, the number of turns and the voltage ratio is given by :

$\dfrac{N_p}{N_s}=\dfrac{V_i}{V_o}\\\\\\V_o=114\cdot\dfrac{8}{475}\\\\V_o=1.92\ V$