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3 years ago

The Doppler Effect is used at baseball games to measure ___________. @3.2.P.B5 @1

Physics

2 answers:

pentagon [3]3 years ago

8 0

Answer: The answer is A. Speed <3

Bogdan [553]3 years ago

3 0

Answer:

Explanation:

Those devices the hold up while the pitcher is pitching measures speed. It has nothing to do with weather and temperature.

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A wire must be replaced in a circuit by a new wire of the same material but nine times longer. If the new wire's resistance is t

Blizzard [7]

Answer:

three times the original diameter

Explanation:

From the wire's resistance formula, we can calculate the relation between the diameter of the wire and its length:

$R=\rho\frac{l}{\pi \frac{d^2}{4}}\\d=\sqrt{\rho \frac{4 l}{\pi R}}\\$

Here, d is the wire's diameter, $\rho$ is the electrical resistivity of the material and R is the resistance of the wire. We have $l'=9l$

$d'=\sqrt{\rho \frac{4 l'}{\pi R}}\\d'=\sqrt{\rho \frac{4 (9l)}{\pi R}}\\d'=3\sqrt{\rho \frac{4 l}{\pi R}}\\d'=3d$

7 0

3 years ago

A 2100 kg car starts from rest and accelerates at a rate of 2.6 m/s2 for 4.0 s. Assume that the force acting to accelerate the c

Reika [66]

When the system is experiencing a uniformly accelerated motion, there are a set of equations to work from. In this case, work is energy which consist solely of kinetic energy. That is, 1/2*m*v2. First, let's find the final velocity.

a = (vf - v0)/t
2.6 = (vf - 0)/4
vf = 10.4 m/s

Then W = 1/2*(2100 kg)*(10.4 m/s)2
W = 113568 J = 113.57 kJ

8 0

3 years ago

A meter stick balances at the 50.0-cm mark. If a mass of 50.0 g is placed at the 90.0-cm mark, the stick balances at the 61.3-cm

Airida [17]

Answer:

126.99115 g

Explanation:

50 g at 90 cm

Stick balances at 61.3 cm

x = Distance of the third 0.6 kg mass

Meter stick hanging at 50 cm

Torque about the support point is given by (torque is conserved)

$mgl_1=Mgl_2\\\Rightarrow M=\dfrac{ml_1}{l_2}\\\Rightarrow M=\dfrac{50\times (61.3-90)}{50-61.3}\\\Rightarrow M=126.99115\ g$

The mass of the meter stick is 126.99115 g

6 0

3 years ago

Read 2 more answers

Three kids are riding on a snow sled traveling horizontally without friction at 19.8 m/s. The masses of Kid A, B, and C are 42.8

Kamila [148]

Answer:

34.6 m/s

Explanation:

From conservation of momentum, the sum of initial and final momentum are equal. Momentum is a product of mass and velocity. Initial mass will be 42.8+31.5+25.9=100.2 kg

Final mass will be 31.5+25.9=57.4 kg

From formula of momentum

M1v1=m2v2

Making v2 the subject of the formula then

$V2=\frac {M1v1}{m2}$

Substitute 100.2 kg for M1, 19.8 m/s fkr v1 and 57.4 kg for m2 then

$V2=\frac {100.2 kg\times 19.8 m/s}{57.4 kg}=34.56376 m/s\approx 34.6 m/s$

4 0

3 years ago

A 250. mL sample of gas at 1.00 atm and 20.0°C has the temperature increased to 40.0°C and the volume increased to 500. mL. What

ladessa [460]

Answer:

New pressure is 0.534 atm

Explanation:

Given:

Initial volume of the gas, V₁ = 250 mL

Initial pressure of the gas, P₁ = 1.00 atm

Initial temperature of the gas, T₁ = 20° C = 293 K

Final volume of the gas, V₂ = 500 mL

Final pressure of the gas = P₂

Final temperature of the gas, T₁ = 40° C = 313 K

now,

we know for a gas

PV = nRT

where,

n is the moles

R is the ideal gas constant

also, for a constant gas

we have

(P₁V₁/T₁) = (P₂V₂/T₂)

on substituting the values in the above equation, we get

(1.00 × 250)/293 = (P₂ × 500)/313

P₂ = 0.534 atm

Hence, the <u>new pressure is 0.534 atm</u>

5 0

3 years ago