The phonograph was invented for people with hearing problems. Option D is correct.
<h3>
What is a Phonograph?</h3>
- It is a device that records sounds or music in the grooves of a plate and plays them.
- This was the first invention that can record and play music.
- It was invented by Thomas Alva Edison.
- This device helps people with hearing problems by allowing them to practice concentrating on a different sound.
Therefore, the phonograph was invented for people with hearing problems.
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Answer:
Inertia Newtons First law
Explanation:
Answer:
The maximum height could be 10.6 meters.
Explanation:
For this kind of exercise, we use the general principle for conservation of mechanical energy (E) that states:
(1)
That means the mechanical energy an object has on a point 2 should be equal to the mechanical energy on a point 1 plus the energy transformed into heat due friction denoted as Wf (It is negative because is lost). In our case point 1 is the point where the roller coaster begins and point 2 is at the second hill. Tola mechanical energy is the sum of potential gravitational energy and kinetic energy, so (1) is :
with K the kinetic energy and U the potential energy, remember potential energy is mgh and kinetic energy is
with m the mass, v the velocity and h the height, then:
Solving for h_2:


Since the collision is inelastic, both vehicle will move with a common velocity of 2.5 m/s in south east direction after collision.
<h3>
Conservation of Linear Momentum</h3>
It states that, the sum of the momentum before collision is equal to the sum of the momentum after collision.
Given that a 7500 kg truck traveling at 5.0 m/s east collides with a 1500 kg car moving at 20 m/s in a direction 30° south of west. After collision, the two vehicles remain tangled together.
The given parameters are;
The formula to find the speed will be
M1U1 - M2U2 = (M1 + M2)V
7500 × 5 - 1500 × 10 = (7500 + 1500)V
37500 - 15000 = 9000V
22500 = 9000V
V = 22500/9000
V = 2.5 m/s
Therefore, the common speed will be 2.5 m/s and the direction of the car will be toward the south east.
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Answer:Take into account the the Earths gravity is 9.8 meters a second
Explanation:
Gravity pulls down on the ball at g=-9.81 m/s^2. Up is positive, down is negative.The ball started at a certain initial velocity of Vi m/s. Time it took is t=4s. Final velocity is Vf=0 m/s, because at the highest point the ball stops moving.
Vf=(g*t)+Vi
Rearrange for Vi.
Vi=Vf-(g*t)
Vi=0-(-9.81*4)=39.24 m/s (upward)
Think about it this way for the non-mathematical approach. The ball stops at the top. The initial velocity gets reduced by 9.81 m/s every second, and reaches 0 m/s at the top. It took 4 seconds, so 9.81*4 is equal to the initial upward velocity.