# Just want to doublecheck answers

Daniiel
I just want to double check that this is right, i have a feeling it's wrong because 570 metres doesnt seem right
1. Homework Statement
A hot air ballon is floating above the surface of a small lake and, in the early morning breeze, is drifting at 5km/h horizontally. A 4.5 kg bag is dropped from the balloon when it is directly above a boat. The bag lands in the water 15m away from the boat. How high is the balloon?

2. Homework Equations

x-x0 = (v0costheta)t
and the vertical formula y-y0 = (vosintheta)-1/2gt^2
3. The Attempt at a Solution
I used the horizontal motion formula to find t
i used the initial velocity as 1.39m/s
x=15
and got t=10.79
then used the vertical formula to find y
which was y = 4.9 x 116.43 = 570

I just followed an example of horizontal and vertical motion in my text book
i think assuming the degree = 0 might of made my answer wrong or somthing
i kinda think that if the balloon was 570 the bag would of landed further than 15m
i apologize for my messiness

I also have another question, sorry im not very confident with physics because theres always somthing im not thinking about.

Question
In order to move a 300kg pallet of bricks across a smooth surface you need a rope tied to the back of your car. If the static friction is 0.2, how much tension is in the rope when the pallet just starts to move?

i just did 300 x 9.8 = 2940N
0.2 x 2940 = 588N
so is the required force to move the pallet 588+2940?
and the tension in the rope when it starts to move 588+2940?

willem2
The first one is correct. People generally underestimate how quickly things fall. In reality the speed at the end of the fall would be 105 m/s and air friction would reduce this a lot.

To move the pallet you only have to overcome the static friction. The 2940 N is the weight of the pallet, you don't have to lift it.

Daniiel