Answer:
μ = 0.18
Explanation:
Let's use Newton's second Law, the coordinate system is horizontal and vertical
Before starting to move the box
Y axis
N-W = 0
N = W = mg
X axis
F -fr = 0
F = fr
The friction force has the formula
fr = μ N
fr = μ m g
At the limit point just before starting the movement
F = μ m g
μ = F / m g
calculate
μ = 34.8 / (19.8 9.8)
μ = 0.18
Answer:

Given:
Mass (m) = 6.8 kg
Speed (v) = 5.0 m/s
To Find:
Kinetic energy (KE)
Explanation:
Formula:

Substituting values of m & v in the equation:




Answer:

Explanation:
As we know by the principle of uncertainty that the product of uncertainty in position and uncertainty in momentum is given as

so here we know that


so we have


Think of the formula force=mass x acceleration. even though they have the same acceleration, a train has more mass. is that helpful?
Mechanical energy is the answer