Answer:
4 m/s
Explanation:
From the law of conservation of momentum,
Total momentum before collision = Total momentum after collision
mu+m'u' = V(m+m')...................... Equation 1
Where m = mass of the arrow, u = initial velocity of the arrow, m' = mass of the apple, u' = initial velocity of the apple, V = Final velocity of the apple and the arrow after collision.
make V the subject of the equation
V = (mu+m'u')/(m+m').................... Equation 2
Given: m = 0.5 kg, m' = 2 kg, u = 20 m/s, u' = 0 m/s(initially at rest)
Substitute into equation 2
V = (0.5×20+2×0)/(2+0.5)
V = 10/2.5
V = 4 m/s.
Hence the final velocity of the apple and the arrow after the collision = 4 m/s
In a completed free body diagram, the diagram should show the magnitude and direction of the body's motion.
Answer:
The object must be placed just ahead of focus towards the lens.
Explanation:
As we know that a magnifying glass is a convex lens and for the convex lens and for a convex lens we get the image virtual, erect and magnified only when it is placed between the optical center and the focus of the lens.
In that range when the object is nearest to the focus of the lens it has the maximum size.
So it can be possible if the object is placed at 9.98 cm from the optical center.
The largest image is formed at infinity when the object is placed at focus but it is not visible to the normal eyes.
Answer:
B: beaks, finches.
Explanation:
Beaks, finches. This is because he noticed that fruit-eating finches had beaks similar to parrots, while finches that ate insects had narrow beaks. The difference in their beaks is due to adapting to different environments which causes them to evolve into different species of finches.
Answer:
electric energy ( power ) = 300000 W
Explanation:
given data
mechanical (hydroelectric) energy = 120 MJ/min = 2000000 J/s
efficiency = 15 % = 0.15
solution
we know that Efficiency of electric engine is expression as
Efficiency = Mechanical energy ÷ electric energy ......................1
and here dam electrical power output is
put here value in equation 1
electric energy ( power ) = Efficiency × Mechanical energy ( power )
electric energy ( power ) = 0.15 × 2000000 J/s
electric energy ( power ) = 300000 W