Question

equations to use
v = δx/δt
x_f=x_i + vt
x_f=x_i+v_ot + 1/2at^2
a = δv/δt
v_f=v_i+at
v_f^2=v_i^2 + 2aδx
a_g = 9.8m/s^2

1. you are driving at 30km/hr.

a. how far will you travel after 4 hours? (120km)
b. your destination is 480 km away, how hours will it take to get to your destination? (16 hours)

1. you drove to school which is a distance of 10km. it took 20 mins. what was your average speed? the displacement was 8km west. what was your average velocity? (30km/hr, 24km/hr west)
2. a car is traveling at a velocity of 30m/s east. the car accelerates for 5 seconds and its new velocity is 45m/s east. what is the car’s acceleration? (3m/s^2)

Explanation:

18. a.

Step1: Identify the formula

Use the formula $x = Vt$, where $V$ is velocity and $t$ is time.

Step2: Substitute values

Given $V = 30$ km/hr and $t = 4$ hr. So $x=30\times4$.

Step1: Identify the formula

Use the formula $t=\frac{x}{V}$, where $x$ is distance and $V$ is velocity.

Step2: Substitute values

Given $x = 480$ km and $V = 30$ km/hr. So $t=\frac{480}{30}$.

Step1: Calculate average speed

First, convert time $t = 20$ mins to hours. Since $1$ hour = 60 mins, $t=\frac{20}{60}=\frac{1}{3}$ hr. Use the formula for average - speed $s=\frac{d}{t}$, where $d = 10$ km. So $s=\frac{10}{\frac{1}{3}}=30$ km/hr.

Step2: Calculate average velocity

Use the formula for average velocity $v=\frac{\Delta x}{t}$, where $\Delta x = 8$ km and $t=\frac{1}{3}$ hr. So $v=\frac{8}{\frac{1}{3}} = 24$ km/hr West.

Answer:

$120$ km

18. b.