he velocity vector is found by taking the displacement divided by the amount of time.
The total displacement is 15 km West.
So the velocity is 15 km W / 45 min.
To convert to km/hr, multiply by 60 min/ 1 hour so the minutes will cancel in the numerator and denominator
15 * 60 / 45 km W / hr = 20 km/h West.
Also sometimes the term "velocity" is used when "speed" is intended in which case you can forget about what direction the movement was in and just say the speed was 20 km/hour.
Also if you want to keep the direction and use vectors, you might have a coordinate system with the x axis going in the East direction, the y axis in the North direction, and assume the world is flat :-) Then if the unit vector for x is "i" and the unit vector for y is "j" then you're looking at a velocity vector that is -20 i (in km/hour).
Work = (force) x (distance)
The work he did: Work = (700 N) x (4m) = 2,800 joules
The rate at which
he did it (power): Work/time = 2,800 joules/2 sec
= 1,400 joules/sec
= 1,400 watts
= 1.877... horsepower (rounded)
A material that is malleable and conducts electricity is
most likely is a metal. The answer is letter C.
The physical property that makes wax good for making
sculpture molds is the melting point. The answer is letter D.
Filtration can be used to separate mixtures based on the
size of their particles. The answer is letter D.
Answer:
Final velocity of the first person is 3.43m/s and that of the second person is 0.0242m/s
Explanation:
Let the momentum of the first person, the ball second person be Ma, Mb and Mc.
From the principle of the conservation of momentum, sum of the momentum before collision is equal to the sum of the momentum after collision.
Ma1 + Mb1 = Ma2 + Mb2.
The ball and the first person are both moving together with a common velocity 3.45m/s.
Let the velocity of the first person be v1
Therefore
67.5×3.45+ 0.041×3.45= 67.5v1 + 0.041×34
233.02 = 1.39+ 67.5v1
67.5v1 = 233.02 - 1.39 = 231.61
v1 = 231.61 / 67.5
v1 = 3.43m/s
The second person and the ball move together with a common velocity after catching the ball.
For the second person and the ball let their final common velocity be v
Mb2 + Mc2 = Mb3 + Mc3
0.041 × 34 + 57.5 ×0 = (57.5 + 0.041)×v
57.541v = 1.39
v = 1.39 /57.541
v = 0.0242m/s
To establish the age of a rock or a fossil, researchers use some type of clock to determine the date it was formed. Geologists commonly use radiometric dating methods, based on the natural radioactive decay of certain elements such as potassium and carbon, as reliable clocks to date ancient events.
