Answer:
8000J
Explanation:
The kinetic energy of the car lost during breaking are converted to thermal energy and are gained by the brakes.
Kinetic energy loss by car = thermal energy gained by brakes.
∆K.E = ∆T.E ....1
The Kinetic energy loss by car can be expressed as;
∆K.E = K.E1 - K.E2
Initial K.E = K.E1 = 10000J
Final K.E = K.E2 = 2000J
∆K.E= 10000J - 2000J = 8000J
From equation 1,
∆K.E = ∆T.E
∆T.E = 8,000J
thermal energy gain by brakes = 8,000J
Answer: 0.5 seconds
Explanation:
Given that:
Frequency of the George Washington Bridge F = 2.05 Hz
Period T = ?
Recall that frequency is the number of cycles a wave can complete in one second. Hence, frequency is the inverse of period.
i.e F = 1/T
2.05Hz = 1/T
T = 1/2.05Hz
T = 0.488 seconds (Rounded to the nearest tenth as 0.5seconds)
Thus, the period of the George Washington Bridge is 0.5 seconds
Answer:
Maximum height attained by the model rocket is 2172.87 m
Explanation:
Given,
- Initial speed of the model rocket = u = 0
- acceleration of the model rocket =
- time during the acceleration = t = 2.30 s
We have to consider the whole motion into two parts
In first part the rocket is moving with an acceleration of a = 85.0 
for the time t = 2.30 s before the fuel abruptly runs out.
Let 
be the height attained by the rocket during this time intervel,
And Final velocity at that point be v
Now, in second part, after reaching the altitude of 224.825 m the fuel abruptly runs out. Therefore rocket is moving upward under the effect of gravitational acceleration,
Let '
' be the altitude attained by the rocket to reach at the maximum point after the rocket's fuel runs out,
At that insitant,
- initial velocity of the rocket = v = 195.5 m/s.
- a =
- Final velocity of the rocket at the maximum altitude =
From the kinematics,
Hence the maximum altitude attained by the rocket from the ground is
Answer:
a. Weight of Object in Water = 20 N
b. Up thrust = 20 N
c. Weight of Water Displaced = 20 N
Explanation:
a.
The weight of the object remains same in the water as well. Because, the same force of gravity is acting there as well. Hence,
<u>Weight of Object in Water = 20 N</u>
<u></u>
b.
Since, the object floats on the water. Therefore, according to Archimedes' principle the up thrust force acting on the object must be equal to the weight of object:
Up thrust = Weight of object
<u>Up thrust = 20 N</u>
<u></u>
c.
From Archimedes' Principle, we know that the up thrust or the Buoyant force is equal to the weight of the water displaced by the object. therefore:
Weight of Water Displaced = Up thrust
<u>Weight of Water Displaced = 20 N</u>
No, that's false. 'Zero' on the Celsius scale
is 273 on the absolute scale.
