True IF the engine is 25% efficient. False otherwise.
Answer:
Stronger and harder than either of the pure metals
Explanation:
1) all matter is made of atoms , atoms are indivisible and indestructible 2) compounds are formed by a combination of two or more different kinds of atoms 3) a chemical reaction is an arrangement of atoms
The terminal speed of the marble is 0.588 m/s.
<h3>Calculation:</h3>
We know that,
F = mg ......(1)
where,
F = force
m = mass
g = acceleration due to gravity
Also,
v = F/k ......(2)
where,
v = terminal speed
k = proportionality constant
Substituting the value of F from equation (1) in equation (2)
v = mg/k .......(3)
Given,
m = 30 g = 0.030 kg
k = 0.500 kg/s
g = 9.8 m/s²
To find,
v =?
Put the values in equation (3)
v = mg/k
v = 0.03(9.8)/ 0.500
= 0.294/0.500
= 0.588 m/s
Hence, the terminal speed of the marble is 0.588 m/s.
Learn more about calculation of force here:
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The sound was repeated because of the phenomenon of echo. The speed of sound in the metal is 800 m/s.
Echo results from the reflection of sound waves. The reason why a sound may be heard twice owes to the phenomenon of reflection which leads to echo.
To determine the speed of sound in the metal;
Length of metal = 1000 m
Time taken between the two sounds = 2.5 s
Using the formula;
V = 2d/t
V = 2(1000)/2.5
V = 800 m/s