Answer:
the potentail of kinetic and potential energy
Explanation:
first explain the concept of kinetic energy (what it is and what its used for) and give examples (cars, a basketball thrown across a hall, and airplane), and do the same with potential energy (the energy an object stores, example: a streched rubber band)
Engineers refine their ideas by making sketches and models.
Answer: A medium in which speed of light is more is known as optically rarer medium and a medium in which speed of light is less is said to be optically denser medium. For example in air and water, air is raer and water is a denser medium.
Explanation:
Answer:
W= - 1414.48 J : Work done by the friction force on the box.
Explanation:
Work concept
The work (W) of a given force is defined as the product of the force (F) by the distance(d) in which the force acted.
W= F*d :in (Joules) Formula (1)
Friction force concept
Ff=μk*N Formula (2)
μk=coefficient of kinetic friction
N= Normal force
We apply Newton's first law for forces in the direction of the axis y
∑Fy=0 Equation (1)
The forces acting on the box in the direction of the axis and are the following:
- Fy=Force of 210 N in y= 210*sen 39°= 132.16 N ( +y)
- W=Weight of box= m*g=30kg*9.8m/s² = 294N (-y)
- N =Normal force ( +y)
We apply equation (1) and do the algebraic sum of forces in y
Fy+N-W=0
132.16+N-294=0
N= 294-132.16=161.84 N
We apply formula (2) to calculate Ff:
Ff= -0.23*161.84=-37,22N The frictional force is negative because it goes in the opposite direction to the displacement.
We apply formula (1) to calculate the work done by the friction force on the box
W= - 37,22 N * 38 m = -1414.48 N*m = -1414.48 J
We have first velocity equals 8 m/s and the kinetic energy is 480 J
The order is the mass of the object
We have this formula K= mv2/2 isolating the mass we have m=k/v2
Now we will have m=480/8×8 > m= 480/64 m= 7.5kg now we deternimed the mass it's 7.5 kg