If the 5,500 J of sound and light is the ONLY useful output
from the phone, then the phone's efficiency is
(5,500J / 10,000J) = 0.55 = 55% .
But the test engineer forgot one little minor almost insignificant detail.
As a test engineer myself, I'd say that he needs to turn in his laptop
and soldering iron, and think about changing his career to a job for
which he may be better suited, like 8 hours a day in a highway toll-booth.
What about that little radio transmitter and receiver inside the phone,
that maintain digital RF communication with the nearest cell tower ?
Without that microscopic radio transceiver ... plus 30 or 40 apps
that are always running unless you shut them off ... the device in your
pocket is essentially a flat rock with one side that sometimes glows.
Answer:
A.Gravity acts to pull the object down
D.The object’s inertia carries it forward.
E.The path of the object is curved.
Explanation:
The motion of a projectile consists of two independent motions:
- A uniform motion along the horizontal direction, with constant horizontal speed
- A vertical motion with constant acceleration of g = 9.8 m/s^2 downward (acceleration due to gravity), due to the presence of the force of gravity, so the vertical velocity changes (increases in the downward direction)
As a result, the combined motion of the projectile has a curved trajectory (parabolic, more specifically). So the following options are correct:
A.Gravity acts to pull the object down --> gravity acts along the vertical direction
D.The object’s inertia carries it forward. --> there are no forces acting along the horizontal direction (if we neglect air resistance), so the horizontal motion continues with constant speed
E.The path of the object is curved
Answer:
1.35 kJ
Explanation:
KE = ½mv² = ½ × 0.030 kg × (300 m·s⁻¹)² = 1350 J = 1.35 kJ
The horizontal speed is going to be the cosine of the given speed, therefore, the horizontal speed is 19.15 m/s. To find the time, divide the 22 m distance by the velocity. This results in 1.131 seconds, which is in between C and D.
Answer:
<em>Magnitude of the Frictional force is 200 N</em>
Explanation:
The frictional force is the force that tries to oppose relative motion between two surfaces that are contacting. The coefficient of static friction is the coefficient of friction of a body that is not moving.
Newton's third law of motion states that action and reaction forces are equal and opposite. So the frictional force felt on the filing cabinet will be equal to the applied force pulling the cabinet.
Frictional force = Force applied
Force applied = 200 N
Therefore, the magnitude of the friction force on the filing cabinet is 200 N
