TEST

Q 1 - Calculate the emissions of a car consuming 5L/100km Ford model \[emissions(gCO_2/100km) = 19.427 + 27.965\times consumption\]

Answer -> C

Explanation

\[emissions(gCO_2/100km) = 19.427 + 27.965\times 5L/100km\] \[emissions(gCO_2/100km) = 124,965gCO_2/100km\]

Q 2 - A car goes 35m/s with an acceleration of 1m/s and a police car get off 10 seconds later with a velocity of 90km/h and acceleration of 5m/s. \[x = x_0 + v\times t + {1\over 2}\times a\times t^2\]
\[v = v_0 + a\times t\]

Q 2.1 - The distance traveled from the car in 10 seconds?

Q 2.2 - The distance traveled from the police in 10 seconds?

Q 2.3 - The time passed when the police catches the car?

Q 2.4 - The distance traveled from both when the police catches the car?

Q 2.5 - The velocity of the police when he catches the car?

Q 2.6 - The velocity of the car when is caught by the police?

Answer 2.1 -> B
Answer 2.2 -> C
Answer 2.3 -> A
Answer 2.4 -> C
Answer 2.5 -> D
Answer 2.6 -> C

Explanation

First of all we need to change 90km/h to m/s \[90km/h*{1000m\over 1km} * {1h\over 3600s} = 25m/s\] Q 2.1 -> \[x_c = 0m + 35m/s \times 10s + {1\over 2}\times 1m/s^2 \times 10^2s\] \[x_c = 400m\]
Q 2.2 -> \[x_p = 0m + 25m/s \times 10s + {1\over 2}\times 5m/s^2 \times 10^2s\] \[x_p = 500m\]
Q 2.3 -> \[x_c = x_p\] \[0m + 35m/s \times (t+10s) + {1\over 2}\times 1m/s^2 \times (t+10s)^2 = 0m + 25m/s \times t + {1\over 2}\times 5m/s^2 \times t^2\] \[t = 20s\]
Q 2.4 -> \[x_c = 0m + 35m/s \times (20s+10s) + {1\over 2}\times 1m/s^2 \times (20+10)^2s\] \[m = 1500m\]
OR
\[x_p = 0m + 25m/s \times 20s + {1\over 2}\times 5m/s^2 \times 20^2s\] \[m = 1500m\]
Q 2.5 -> \[v_p = 25m/s + 5m/s^2\times 20s\] \[v_p = 125m/s\]
Q 2.6 -> \[v_c = 35m/s + 1m/s^2\times 20s\] \[v_c = 55m/s\]

Q 3 We have a car with 25% of efficiency, it produces 2,5kw each hour. \[\eta = {E_{produced}\over E_{consumed}}\] \[E_{lost} = E_{consumed} - E_{produced}\]

Q 3.1 How much energy have the car?

Q 3.2 How much energy we lose in heat in 8 hours?

Answer 3.1 -> C
Answer 3.2 -> D

Explanation

First of all we need to pass \[25{%} = 0.25\]
Q 3.1 -> \[0.25 = {2.5kW\over E_{consumed}}\]
\[E_{consumed} = {2.5kW\over 0.25}\]
\[E_{consumed} = 10kW\] Q 3.2 -> \[E_{lost} = 10kW - 2.5kW\]
\[E_{lost} = 7.5kW\]
\[E_{lost}8h = 7.5kW * 8h\]
\[E_{lost}8h = 60kWh\]

Q 4 - You have a car which massa is 5000kg and which velocity is 10m/s. What is the power of this car? \[F = m * a\]

Answer -> A

Explanation

Q 4 -> \[F = 5000kg * 10m/s\]
\[F = 50000N\]

Q 5 - What are the forces that appear in the car when it hits the wall

A - one P, one N

B - one F, three N

C - two P, one F, one N

D - two N, one P, one F

Answer -> B

Explanation

Q 5 -> The normal between the car and the wall and the normal between the car and the floor. The weight of the car and the power between the car and the wall.