What should students do before inserting the plug of an electrical device into a socket?

The force diagram represents a girl pulling a sled with a mass of 6.0 kg to the left with a force of 10.0 N at a 30.0 degree ang

STatiana [176]

the correct answers are 54N and -1,2m/s^2

6 0

3 years ago

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a toy dart gun has a spring with k=128 N/m. a kid pulls back on the spring with a 8.22 N force. how far does it stretch?(unit=m)

german

Answer:

0.064 m

Explanation:

When a spring is stretched/compressed, the force exerted in the spring is related to the elongation of the spring by the equation:

$F=kx$

where:

F is the force applied

k is the spring constant

x is the stretching/compression of the spring

In this problem, we have:

$F=8.22 N$ is the force applied by the kid on the spring

k = 128 N/m is the spring constant

Solving for x, we find how far the spring stretches:

$x=\frac{F}{k}=\frac{8.22}{128}=0.064 m$

8 0

3 years ago

For a projectile launched at an angle, are the forces in the vertical direction balanced or unbalanced?

mart [117]

Unbalanced as long as it is moving up or down. Immediately after being fired the vertical force from the launch will be greater than the force of gravity. for an instant at the the beginning of the projectiles decent the force will actually be balanced and there will be no vertical movement. After that the force of gravity is greater.

tl;dr they are unbalanced

7 0

3 years ago

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0.3-L glass of water at 20C is to be cooled with ice to 5C. Determine how much ice needs to be added to the water, in grams, i

abruzzese [7]

Answer:

$a. m_i_c_e=54.6g\\b. m_i_c_e=48.7g\\m_c_o_l_d_w_a_t_e_r=900g$

Explanation:

First we need to state our assumptions:

Thermal properties of ice and water are constant, heat transfer to the glass is negligible, Heat of ice $h_i_f=333.7KJkg$

Mass of water, $m_w=\rho V =1\times0.3=0.3Kg$ .

Energy balance for the ice-water system is defined as

$E_i_n-E_o_u_t=\bigtriangleup E_s_y_s\\0=\bigtriangleup U=\bigtriangleup U_i_c_e+\bigtriangleup U_w$

a.The mass of ice at $0\textdegree C$ is defined as:

$[mc(0-T_1)+mh_i_f+mc(T_2-0)]_i_c_e+[mc(T_2-T_1)]_w=0\\\\m_i_c_e[0+333.7+418\times(5-0)]+0.3\times4.18\times(5-20)=0\\m_i_c_e=0.0546Kg=54.6g$

b.Mass of ice at $20\textdegree C$ is defined as:

$[mc(0-T_1)+mh_i_f+mc(T_2-0)]_i_c_e+[mc(T_2-T_1)]_w=0\\\\m_i_c_e[2.11\times(0-(20))+333.7+4.18\times(5-0)]+0.3\times4.18\times(5-20)=0\\\\m_i_c_e=0.0487Kg=48.7g$

c.Mass of cooled water at $T_c_w=0\textdegree C$

$\bigtriangleup U_c_w+\bigtriangleup U_w=0$

$[mc(T_2-T_1)]_c_w+[mc(T_2-T_1)]_w=0\\m_c_w\times4.18\times(5-0)+0.3\times4.18\times(5-20)\\m_c_w=0.9kg=900g$

8 0

3 years ago

[URGENT] A swimmer wants to end up at a dock due north of her starting position on the south shore of a river. In still water he

Stells [14]

Explanation:

As you can see in the picture, we want the swimmer to go on a straight line, so the speed of the water must be equal to the speed of the swimmer along the x-axis. We also know the value of v, so we can calculate the of the cosine of the angle (alpha) between Vx and V. Thanks to the fundamental relation of gioniometry (cos^2(x) + sin^2(x) = 1) we can find the sine of alpha and calculate Vy. With Vy we can calculate the time that the swimmer will use for reaching the dock: s = Vy * t => t = s/(Vy).

I'll let you do all the calculations, you just have to plug in values.

6 0

3 years ago