Answer:
20cm
Explanation:
A convex lens has a positive focal length and the object placed in front of it produce both virtual and real image <em>(image distance can be negative or positive depending on the nature of the image</em>).
According to the lens equation
where;
f is the focal length of the lens
u is the object distance
v is the image distance
If the magnification is - 0.6
mag = v/u = -0.5
v = -0.5u
since v = 10cm
10 = -0.5u
u = -10/0.5
u =-20 cm
Substitute u = -20cm ( due to negative magnification)and v = 10cm into the lens formula to get the focal length f

Hence the focal length of the convex lens is 20cm
It is simply called Entropy.
The velocity of the ball when it strikes the ground, given the data is 21.56 m/s
<h3>Data obtained from the question</h3>
From the question given above, the following data were obtained:
- Time to reach ground from maximum height (t) = 2.2 s
- Initial velocity (u) = 0 m/s
- Acceleration due to gravity (g) = 9.8 m/s²
- Final velocity (v) =?
<h3>How to determine the velocity when the ball strikes the ground</h3>
The velocity of the ball when it strikes the ground can be obtained as illustrated below:
v = u + gt
v = 0 + (9.8 × 2.2)
v = 0 + 21.56
v = 21.56 m/s
Thus, the velocity of the ball when it strikes the ground is 21.56 m/s
Learn more about motion under gravity:
brainly.com/question/22719691
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Answer:
The speed of the sled is 3.56 m/s
Explanation:
Given that,
Mass = 2.12 kg
Initial speed = 5.49 m/s
Coefficient of kinetic friction = 0.229
Distance = 3.89 m
We need to calculate the acceleration of sled
Using formula of acceleration

Where, F = frictional force
m = mass
Put the value into the formula




We need to calculate the speed of the sled
Using equation of motion

Where, v = final velocity
u = initial velocity
a = acceleration
s = distance
Put the value in the equation



Hence, The speed of the sled is 3.56 m/s.