The average velocity = Displacement between two points/ Time taken for that displacement
In this case An ion's position vector is initially r = 8.0 i - 4.0 j + 3.0 k, and 8.0 s later it is r = 4.0 i + 8.0 j - 6.0 k
So, displacement = 4.0 i + 8.0 j - 6.0 k - (8.0 i - 4.0 j + 3.0 k)
= -4.0 i + 12.0 j - 9.0 k
So velocity, V = (-4.0 i + 12.0 j - 9.0 k)/8
= -0.5 i + 1.5 j - 1.125 k
So average velocity during 8 seconds = -0.5 i + 1.5 j - 1.125 k
Answer:
500 m/s
Explanation:
Momentum, p is a product of mass and velocity. From law of conservation of momentum, the initial momentum equals final momentum

Here m and v represent mass and velocity respectively and subscripts 1 and 2 represent car and barrier respectively
Therefore, the velocity of barrier will be 500 m/s
This would be Newton's first law, which states that an object at rest will stay at rest and an object in motion will remain in motion unless acted on by an unbalanced force. Hope this helped.
Answer:
τ=0.060 N.m
Explanation:
By kinematics:

Solving for α:

where ωo = 600*2*π/60; ωf = 0; t=10s

The sum of torque is:



Answer : The velocity of an electron is, 
Explanation :
According to de-Broglie, the expression for wavelength is,

and,

where,
p = momentum, m = mass, v = velocity
So, the formula will be:
.............(1)
where,
h = Planck's constant = 
= wavelength = 
m = mass of electron = 
v = velocity of electron = ?
Now put all the given values in formula 1, we get:


Thus, the velocity of an electron is, 