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Papessa [141]
3 years ago
10

A hoodlum throws a stone vertically downward with an initial speed of 12.0 m/s from the roof of a building,30.0 m above the grou

nd. (a) how long does it take the stone to reach the ground
Physics
1 answer:
bogdanovich [222]3 years ago
8 0
S=ut +1/2at2
30=12t+1/2*10*t2
5t2+12t-30=0
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A thin, circular hoop with a radius of 0.22 m is hanging from its rim on a nail. When pulled to the side and released, the hoop
Alex73 [517]

Answer:

Period of oscillation = 1.33 seconds

Explanation:

The period of oscillation is given by:

T = 2π√[I/(MgL)] 

for I = 2MR² and L = R,

Given: L = 0.22m = R

T = 2π√[2R/g] 

T = 2 × 3.142 Sqrt[( 2 × 0.22)/ 9.8]

T = 6.284 Sqrt(0.44/9.8)

T = 6.284 Sqrt(0.0449)

T = 6.284 × 0.2119

T = 1.33 sec

6 0
4 years ago
A beaker of vegetable oil contains a beam of light that is aimed at a surface at an angle of 34 degrees as shown. If the index o
OverLord2011 [107]

Answer:

Angle of reflection of light is 34 degree

Explanation:

As per law of reflection of light we know that

angle of incidence of light = angle of reflection of light

So here we know that

angle of incidence on the surface of oil is given as

\theta_i = 34 degree

so we know that

\theta_i = \theta_r

so here we can say that reflection angle of light will be same as angle of incidence

\theta_r = 34 degree

8 0
3 years ago
n the figure, a uniform ladder 12 meters long rests against a vertical frictionless wall. The ladder weighs 400 N and makes an a
Leto [7]

Since the ladder is standing, we know that the coefficient of friction is at least something. This [gotta be at least this] friction coefficient can be calculated. As the man begins to climb the ladder, the friction can even be less than the free-standing friction coefficient. However, as the man climbs the ladder, more and more friction is required. Since he eventually slips, we know that friction is less than what's required at the top of the ladder.

 

The only "answer" to this problem is putting lower and upper bounds on the coefficient. For the lower one, find how much friction the ladder needs to stand by itself. For the most that friction could be, find what friction is when the man reaches the top of the ladder.

Ff = uN1

Fx = 0 = Ff + N2

Fy = 0 = N1 – 400 – 864

N1 = 1264 N

Torque balance

T = 0 = N2(12)sin(60) – 400(6)cos(60) – 864(7.8)cos(60)

N2 = 439 N

Ff = 439= u N1

U = 440 / 1264 = 0.3481

3 0
3 years ago
Read 2 more answers
While the block hovers in place, is the density of the block (top left) or the density of the liquid (bottom center) greater?
Licemer1 [7]

Answer:

for the body to float, the density of the body must be less than or equal to the density of the liquid.

Explanation:

For a block to float in a liquid, the thrust of the liquid must be greater than or equal to the weight of the block.

Weight is

        W = mg

let's use the concept of density

        ρ_body = m / V

        m = ρ_body V

        W = ρ_body V g

The thrust of the body is given by Archimedes' law

        B = ρ_liquid g V_liquid

 

as the body floats the submerged volume of the liquid is less than or equal to the volume of the block

       ρ_body V g = ρ_liquid g V_liquid

     

       ρ_body = ρ liquid Vliquido / V_body

As we can see, for the body to float, the density of the body must be less than or equal to the density of the liquid.

3 0
4 years ago
A current exists whenever electric charges move. If ΔQ is the net charge that passes through a surface during a time period Δt,
jeka57 [31]

Answer:

It represents the change in charge Q from time t = a to t = b

Explanation:

As given in the question the current is defined as the derivative of charge.

                                  I(t) = dQ(t)/dt ..... (i)

But if we take the inegral of the equation (i) for the time interval  from t=a to

t =b we get

                                   Q =∫_a^b▒〖I(t)  〗 dt

which shows the change in charge Q from time t = a to t = b. Form here we can say that, change in charge is defiend as the integral of current for specific interval of time.

5 0
4 years ago
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