Answer:
Explanation:
mass of box, m = 60 kg
distance, d = 6.2 m
force, P = 150 N
coefficient of kinetic friction, μk = 0.21
work done by the gravitational force, Wg = Force x distance x cos 90
Wg = 0 J
Work done by the normal force, Wn = force x distance x Cos 90
Wn = 0 J
Work done by the friction force, Wf = - μk mg d
Wf = - 0.21 x 60 x 9.8 x 6.2 = - 765.58 J
Work done by the applied force, Wp = P x d
Wp = 150 x 6.2 = 930 J
Answer:
Chemical energy to electrical energy
Explanation:
In nature, there are several types of energy.
In this example (a flashlight being turned on), we have a conversion of energy from chemical energy to electrical energy. In fact:
- Chemical energy is the energy stored in the chemical bonds of the molecules of the substances used inside the battery. When the chemical reaction inside the battery occurs, this energy is liberated, and it is used to "push" the electrons along the circuit connected to the battery
- Electric energy is the energy associated to the motion of the electrons along the circuit of the flashlight; it is the energy associated to an electric current.
Moreover, in the flashlight the electric energy is then converted into two more types of energy: light energy (since the bulb in the flashlight produces light) and heat energy (because the flashlight also produces heat, so thermal energy).
Scales measure how much something weighs—and they do it by measuring how much force exists between the object you're weighing and planet Earth. Although scales measure force, they give you measurements of mass in kilograms, grams, pounds, or whatever.
Explanation:
The efficiency of a machine is 70% means 30% of the applied force is wasted in overcoming friction and 70% of the applied force is used to do the work
Answer:
w=3.05 rad/s or 29.88rpm
Explanation:
k = coefficient of friction = 0.3900
R = radius of the cylinder = 2.7m
V = linear speed of rotation of the cylinder
w = angular speed = V/R or to rewrite V = w*R
N = normal force to cylinder
N=
These must be balanced (the net force on the people will be 0) so set them equal to each other.
There are 2*pi radians in 1 revolution so:
So you need about 30 RPM to keep people from falling out the bottom
