Question

1. If Mike drove for nine hours at a speed of 105km/h, how far did he drive in meters (m)?

Answer 1

Answer:

1) 945.000 meters

2) 9,84 kilometers/hour

3) 3,52 seconds

Explanation:

1) 105 km/h x 9 h = 945km

1km = 1000 meters    945 km = 945.000 meters

2) 1 mile = 1.61 km

5.5 miles x 1.61 km / 1 mile = 8,855 km

You have to do a single third rule to clear the x which is the Ann's velocity in 1 hour.

8,855km in 0.9 hs

x (velocity in 1 hour) = 9,84 km =   1 hs

1 hs x 8,855km / 0,9hs = 9,84km/h

v= 9,84km/h

3) you have to use this formula and clear T (time)

vf = v0 + a.t

vf-v0 = a.t

(vf - v0)/a = t

(33.7 m/s - 18.9 m/s) / 4.2 m/s2 = 3,52 seconds

Answer 2

Answer:

1) 945000 m

2) 6.11 miles/hour

3) 3.52 seconds

Explanation:

1. Speed is the time rate of change of distance, it is the ratio of distance to time. Speed is given by the equation:

$speed(S)=\frac{distance(d)}{time(t)}$

Given that:

Time (t) = 9 hours and Speed (S) = 105 km/h

$S=\frac{d}{t}\\ d=S*t=105*9=945km=945000m$

2) Time (t) = 0.9 hours and distance (d) = 5.5 miles

$S=\frac{d}{t}\\ S=\frac{5.5}{0.9} =6.11miles/hour$

3) Acceleration it is the ratio of velocity to time. Acceleration is given by the equation:

$Accceleration(a)=\frac{Final,velocity(u)-initial, velocity(v)}{time(t)}$

Given that :

a = 4.2 m/s² , u = 18.9 m/s and v = 33.7 m/s

$a=\frac{v-u}{t}\\ t=\frac{v-u}{a}\\ t=\frac{33.7-18.9}{4.2}=3.52s$