Here i state the conservation of energy rule and use that to justify my answer. I showed how to manipulate percentages to get the final answer of 11000J (2sf). Hope I'm right xx
Answer:
<em>a. True</em>
<em></em>
Explanation:
I'll assume the question is about magnetic latches and locks.
Magnetic door locks use an electromagnetic force to stop doors from opening, so they are ideal for security. There are two main types of electric locking devices. Locking devices can either be a fail-secure locking device that remains locked when power is lost, or a fail-safe locking device that is unlocked when de-energized. An electromagnetic lock creates a magnetic field when energized or powered up, this causes an electromagnet and armature plate to become attracted to each other strongly enough to keep a door from opening.
Between magnitude of the average 4sec
Answer:
<h2>
The answer is </h2><h2>
a. 5g/mL</h2>
Explanation:
Given data
mass m= 45g
volume v= 9mL
we know that density=m/v
substituting our given data we have
What is Density?
The Density of a body can be defined as the ratio of mass to volume,
or
Density, mass of a unit volume of a material substance. The formula for density is 
,
where d is density,
M is mass, and
V is volume.
Density is commonly expressed in units of grams per cubic centimetre.
Answer:
-35 m/s
Explanation:
Momentum is conserved.
Momentum before firing = momentum after firing
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
Before the bullet is fired, the bullet and rifle have no velocity, so u₁ and u₂ are 0.
0 = m₁v₁ + m₂v₂
Given m₁ = 0.7 kg, v₁ = 350 m/s, and m₂ = 7 kg:
0 = (0.7 kg) (350 m/s) + (7 kg) v
v = -35 m/s
The rifle recoils at 35 m/s in the opposite direction.
