You have constructed a raft that is 2.00 m long, 2.00 m wide, and 0.100 m thick. Part A If the mass of the raft is 20.0 kg and your mass is 55.0 kg, how many 65.0 kg friends can cross a river with you during one trip

5

Explanation:

Volume of raft,

Density of raft,

Total weight= Buoyant force

Assuming n number of friends weighing 65 Kg then

(20+55+65n)g= Buoyant force

Buoyant force will be given by multiplying density of water by volume by acceleration due to gravity

g is on both sides so they cancel

75+65n=400

65n=400-75=325

Therefore, 5 friends each weighing maximum of 65 Kg can go with you on one trip

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s