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3 years ago

When throwing a ball upwards, the velocity is positive, and the acceleration is negative. True of False?

Physics

1 answer:

Setler79 [48]3 years ago

3 0

Answer:

The velocity & acceleration will be taken as negative when a ball is thrown upward because work is done against the gravity.

Explanation:

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In a series circuit, loads which have the same voltage dropped across them will have ? .

Nadusha1986 [10]

The same as the voltage in all bulbs. The series circuit is a pattern of the circuits in which the loads will have the same amount of power and consumed voltage. If one load goes out, the others will turn off also. This is because they have connected wires and pattern.

5 0

3 years ago

2. Michelle bought 15.6 yards of fabric. She used 5.43 yards in her art installation. About what percent of the fabric did she u

photoshop1234 [79]

35%
5.43/15.6
This is how you calculate the percentage the answer is 35%

4 0

3 years ago

An 89.0 kg fullback moving east with a speed of 5.6 m/s is tackled by an 85.0 kg opponent running west at 2.84 m/s, and the coll

Korolek [52]

Answer:

a. $v_f=1.477m/s$

b. Δ $K=1558.3J$

c. $E_k=1034.7 J$

Explanation:

a).

Momentum conserved

$p_{ix}=p_{fx}$

$m_1*v_1+m_2*v_2=(m_1+m_2)*v_f$

$v_f=\frac{m_1*v_1+m_2*v_2}{m_1+m_2}$

$v_f=\frac{89.0kg*5.6m/s+85.0kg*-2.84m/s}{(89.0+85.0)kg}$

$v_f=1.477m/s$

b).

Δ $K=K_i-K_f$

$\frac{1}{2}*m_1*v_1^2+\frac{1}{2}*m_2*v_2^2=\frac{1}{2}*(m_1+m_2)*v_f^2$

$\frac{1}{2}*89.0kg*(5.6m/s)^2+\frac{1}{2}*85.0kg*(2.84m/s)^2=\frac{1}{2}*(89.0+85.0)kg*(1.447m/s)^2$

Δ $K=1558.3J$

c).

$E_k=\frac{1}{2}*89kg*(5.8m/s)^2-\frac{1}{2}*(85+89)kg*(1.44m/s)^2$

$E_k=1034.7 J$

d).

All of which has been lost as mechanical energy, and is now thermal energy warmer football players, noise a loud crunch for example.

8 0

3 years ago

Một mặt phẳng vô hạn tích điện đều, mật độ σ = 4.10-9 C/cm2, đặt thẳng đứng trong không khí. Một quả cầu nhỏ có khối lượng 8 g,

dusya [7]

Answer:

The angle is 18.3 degree.

Explanation:

A uniformly charged infinite plane, density σ = 4 x 10^-9 C/cm^2, is placed vertically in air. A small ball of mass 8 g, with charge q = 10^-8 C, hangs close to the plane, so that the string is initially parallel to the plane. Take g = 9.8m/s2. When in equilibrium, by what angle is the string hanging the ball to the plane?

surface charge density, σ = 4 x 10^-5 C/m^2

Charge, q = 10^-8 C

mass, m = 0.008 kg

Let the angle is A and the tension in the string is T.

The electric field due to a plane is

$E =\frac{\varepsilon \sigma }{2\varepsilon o}\\\\E =\frac{4\times 10^{-5}}{2\times 8.85\times 10^{-12}}\\\\E = 2.26\times 10^6 V/m \\$

Now equate the forces,

$T sin A = q E.... (1)\\\\T cos A = m g ..... (2)\\\\divide (1) by (2)\\\\tan A = \frac{10^{-8}\times 2.6\times 10^6}{0.008\times 9.8}\\\\tan A = 0.33\\\\ A = 18.3 degree$

5 0

3 years ago

Is work being done when you carry something?

wlad13 [49]

Answer:

Yes you are using energy to carry that thing.(Force is applied)

Explanation:

8 0

3 years ago