Answer:
36 km/h
Explanation:
The total velocity is the sum of the two velocities that add to the movement of the boat.
Since the wind pushes the boat at 21 km/h and the current that runs in the direction of the movent of the boat is 15 km/h, the total velocity at wich the boat moves is:
21km/h + 15 km/h = 36 km/h
The magnitude of the change in momentum of the block between zero and 4. 0 seconds is
dp=1.6m/s
<h3>What is the magnitude of the change in momentum of the block between zero and 4. 0 seconds?</h3>
Generally, the equation for the kinematics equation is mathematically given as
x=x+ut+0.5at^2
Therefore
1.6=0+0+0.5*a*1^2
a=0.2m/s^2
In conclusion, change in momentum
dP=mv-mu
2.0*0.8-0
dp=1.6m/s
Read more about Force
brainly.com/question/13370981
Answer:
Light does not need a medium to travel travel through, but since waves must have a medium to vibrate, sound is not created where no air is present.
Explanation:
Answer:
<h3>2139 Million years</h3>
Explanation:
Half life of a material is the time required for the material to decay into half of initial amount.
initially there is 26 grams of uranium-235, and the final amount is 3.25 gram
ratio between initial and final amount = 
now it is clear that the material have halved 3 times from initial condition
number of half lives passed = 3
number of half lives passed can also be found using the equation
no of half lives = 
where 
is the initial amount of material and R is the final amount
∵ Number of half lives = 
= 3
So, age of rock = half-life X number of half-lives passed
=713000000 X 3
= 2139000000
=2139 Million Years
