1- Ann is driving down a street at 60 km/h.
Suddenly a child runs into the street.
If it takes Ann 0.774 s to react and apply
the brakes, how far will she have moved before
she begins to slow down?
Answer in units of m.
2- A glacier advances at 4.8 × 10−6 cm/s.
How far will it move in 75000 s?
Answer in units of cm.
How far will it move in 6.4 y?
Answer in units of cm.
3- A polar bear starts at the North Pole. It
travels 1 km South, then 1 km East, then
1 km North to return to its starting point.
This trip takes 0.5 h.
What was the bear’s average velocity?
Answer in units of km/h.
2. Multiply the time and the speed, the units cancel.
4.8x10^-6 X 75000s = 3.6 cm
Find the total seconds in a year.
60 seconds x 60 minutes x 24 hours x 365 days = 31536000 seconds.
Multiply by the speed, the units cancel.
4.8x10^-6 X 31536000s = 1513.728 cm
1. Convert 0.774 seconds to hours.
0.774s X 1/360h/s = 0.774/360 = 0.00215h
Multiply by the speed, the units cancel.
0.00215 X 60km/h = 0.129km
Convert to meters from kilometers
0.129km X 1000m/km = 129 Meters
3. Direction means nothing in this question. The bear traveled 3 km in 0.5 hours. so that's your speed. 3/0.5 km/h. Simplify the fraction and get 6km/h.
always convert to m.s^-1 when working with equations of motion,
