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3 years ago

Choose the correct statement regarding the sign conventions for lenses.

Physics

1 answer:

Savatey [412]3 years ago

3 0

Answer:

a) false

b) True

c) True

d) False

e) False

Explanation:

a) False

For a diverging lens, the focal length is negative while it is positive for a converging lens

b) True

Image distances for virtual images are always negative and it also forms on the the same side of the lens as the object and is enlarged

c) True

d) False

For a diverging lens, the focal length is negative while it is positive for a converging lens

e) False

Image distances for virtual images are always negative and it also forms on the the same side of the lens as the object and is enlarged

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A scooter has a mass of 250. Kg. A constant force is exerted on it for 60.0 S. during the time the force is exerted, the scooter

kodGreya [7K]

Answer:

Explanation:

change in momentum = m ( v - u ) ; m is mass , V is final velocity and u is initial velocity .

= 250 ( 28 - 6 )

= 5500. N.s

for calculating magnitude of force we shall apply the concept of impulse

Impulse = F X t = m( v-u ) ; F is force applied for time t .

F x 60 = 5500

F = 91.67 N .

force exerted = 91.67 N .

8 0

3 years ago

You are designing a system for moving aluminum cylinders from the ground to a loading dock. You use a sturdy wooden ramp that is

8_murik_8 [283]

Answer:

a = αR

Then We apply the Newton's second law of motion:

∑ F = ma

F - mg sinθ - f = ma.

F - mg sinθ - μmg cosθ = ma

Using given data we have:

F - 3217 = 470a ........................... (1)

Apply the Newton's law for rotation:

∑τ = I α

FR - (mg sinθ)R = $(\frac{mR^2}{2}+mR^2)\frac{a}{R}$

then: F - mg sinθ = 3ma / 2.

F - 2774 = 705a .......................... (2)

solving 1 and 2 we get:

F = 4103 N

a = 1.885 m/s²

b) In this case the time is given by:

t = $\sqrt{\frac{2d}{a}}$ it comes from: d = $v_ot+\frac{1}{2}at^2$ starting from rest vo = 0

t = $\sqrt{\frac{2*9}{1.885}$ = 3.09 s

8 0

3 years ago

If a ball is thrown straight up into the air with an initial velocity of 40 ft/s, it height in feet after t second is given by y

Tasya [4]

We should first calculate the highest point that ball reaches.
y' = 40 - 32t = 0
t = 40/32 = 1,25s
y = 25 feet.

To calculate average velocity we use simple formula:
Vav=s/t where s is traveled distance by the time t.

for t=2 we calculate y
y = 16
(i) for t = 2,5 y = 0
Vav = 16/0.5 = 32 feet/s
(ii) for t = 2.1 y = 13.44
Vav = 2.56/0.1 = 25.6 feet/s
(iii) for t = 2.01 y = 15.7584
Vav = 0.2416/0.01= 24.16 feet/s

it seems like the answer would be 24 feet/s. There is a way to calculate that.

5 0

3 years ago

(10%) Problem 10: A 7.25-kg bowling ball moving at 9.85 m/s collides with a 0.875-kg bowling pin, which is scattered at an angle

siniylev [52]

Answer

given,

mass of bowling ball = 7.25 Kg

moving speed of the bowling ball = 9.85 m/s

mass of bowling in = 0.875 Kg

scattered at an angle = θ = 21.5°

speed after the collision = 10.5 m/s

angle of the bowling ball