Answer:
3.6 m/s
Explanation:
From the law of conservation of momentum,
Total momentum before jump = Total momentum after jump
<em>Note: Before Dan jump off the skateboard, they where both moving with the same velocity</em>
u(m+m') = mv+m'v'................. Equation 1
Where m = Dan's mass, m' = mass of the skateboard, u = common velocity before the jump, v = Dan's final velocity, v' = The final velocity of the skateboard.
make v the subject of the equation
v = [u(m+m')-m'v')]/m.............. Equation 2
Given: u = 4.0 m/s, m = 50 kg, m' = 5 kg, v' = 8 m/s
Substitute into equation 2
v = [4(50+5)-(5×8)]/50
v = (220-40)/50
v = 180/50
v = 3.6 m/s
I believe because there is much less air and much more water in the bottom
Gravitational Potential Energy, GPE = mgh
Where m is your mass in kg, g is acceleration due to gravity = 9.8 m/s², and h is the height in m.
The only value that be controlled here is the height h. The mass is constant, and acceleration due to gravity at that place is constant.
But h can be varied.
Hence to increase the gravitational potential energy between yourself and Earth is to increase the height h.
This can be done by climbing up a table, or climbing up a building through the stairs, or by using a lift.
B. A sandbar is formed by water. A sand dune is formed by wind.
Answer:
please read the answer below
Explanation:
The angular momentum is given by
By taking into account the angles between the vectors r and v in each case we obtain:
a)
v=(2,0)
r=(0,1)
angle = 90°
b)
r=(0,-1)
angle = 90°
c)
r=(1,0)
angle = 0°
r and v are parallel
L = 0kgm/s
d)
r=(-1,0)
angle = 180°
r and v are parallel
L = 0kgm/s
e)
r=(1,1)
angle = 45°
f)
r=(-1,1)
angle = 45°
the same as e):
L = 5kgm/s
g)
r=(-1,-1)
angle = 135°
h)
r=(1,-1)
angle = 135°
the same as g):
L = 5kgm/s
hope this helps!!
