Answer:
Power = 30 [watts]
Explanation:
Initia data:
F = force = 30[N]
d = displacement = 2 [m]
By definition we know that work is equal to the product of force by the distance displaced
Therefore:
W = F * d = 30 * 2
W = 60 [J]
And power is defined as the amount of work done in a given time interval
time = t = 2 [sec]
Power = W / t
Power = 60 / 2
Power = 30 [W]
Answer:E
=
252
J
Explanation:
The total mechanical energy of an object or system is given by:
E
m
e
c
h
=
K
+
U
Where
K
is the kinetic energy of the object and
U
is the potential energy of the object. The carriage, sitting motionless at the top of the hill, has only potential energy in the form of gravitational potential energy.
Gravitational potential energy is given by:
U
g
=
m
g
h
Where
m
is the mass of the object,
g
is the gravitational acceleration constant, and
h
is the height of the object above some specific reference point, in this case the ground
21
m
below.
The weight of a stationary object at the surface of the earth is equal to the force of gravity acting on the object.
W
=
→
F
g
=
m
g
We are given that the carriage weighs
12
N
, therefore
m
g
=
12
N
.
U
g
=
12
N
⋅
21
m
⇒
U
g
=
252
N
m
=
252
J
Answer link
Explanation:
Answer:
correct answer is (c) 15 J
Explanation:
given data
mass m1 = 2 kg
velocity V1 = 5 m/s
mass other = 3 kg
so mass m2 = 2+ 3 kg = 5 kg
solution
we will apply here conservation of momentum:
m1V1 = m2V2 ..........................1
put here value and we get velocity v2
(2.0) × (5.0) = (2.0 + 3.0) × V
solve it we get
10 = 5 × V
2
V2 = 2.0 m/s
so here kinetic energy will be
KE = ½ × m × v²
so
∆KE = ½ × m1 × (v1)² - ½ × m2 × (v2)
²
∆KE = 0.5 × 2 × 25 - 0.5 × 5 × 4
∆KE = 25 - 10
∆KE = 15 J
The figure shown below illustrates a lever being used to lift a weight W.
The applied force is F.
In order to lift the weight, the minimum applied force is
F*b = W*a
F = (a/b)W
When the ratio a/b < 1, then the applied force is less than the weight.
The principle behind the use of a lever is to keep the ratio a/b small in order to decrease the effort force.
Answer: A
A lever is used to decrease effort force.
Answer:
q2 = 5.1μC
Explanation:
From a forces diagram we can stablish that:
Fe = T*sin(16) (eq1)
T*cos(16) = m*g (eq2)
Where Fe is the electric force and T is the tension of the string. Solving for Fe:
Fe = m*g*tan(16)
The magnitude of the electric force is calculated as:
Solving for q2:
