- #1

alexandria

- 169

- 2

Member reminded that separate problems should be given separate threads.

## Homework Statement

so I am sending my unit in for marking, and i collected a bunch of kinematic related questions that I've attempted to answer, but don't know if I am on the right track. Any help would be appreciated. Thanks.

1.[/B]

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## Homework Equations

relevant equations are listed with each question

## The Attempt at a Solution

1.

The truck traveled 14.0 km (South) in 15 min. The truck continued another 6 km at a slower pace over 10 min, and then stayed at this location for 5 min. The truck continued on at a constant speed for another 8 km towards the destination, taking 15 min for this portion of its journey.

2.

Displacement = 131 km (South)

Average velocity = total displacement / total time

Average velocity = 131 km (S) / 2.0 h

Average velocity = 65.5 km /h (south)

3.

a)

d = v x t

__Time to cross river:__

t = d / v

= 0.032 km / 2.5 km/h

= 0.0128 hrs

__Walking distance:__

d = (1.2 km/h) x (0.0128 hrs)

d = 0.01536 km = 15.36 m

Sandra will have to walk 15.36 m to reach the farmer’s market.

b)

**Time it takes to cross the river:**

t = d / v

t = 32.0 m (E) / 0.69 m/s (E)

t = 46 s

**Time it takes to walk the riverbank:**

t = d / v

t = 15.36 m / 0.72 m/s

t = 21 s

Walking to the farmer’s market will result in the shortest time for Sandra to reach her destination.

4.

Increase the launch angle above 45 degrees, to reduce the horizontal displacement. This way the water balloon will hit the target instead of passing it.

5.

is it because the supplies will be blown off course??