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3 years ago

How much heat energy (in megajoules) is needed to convert 7 kg of ice at -9°C C to water at 0°C?

Physics

1 answer:

Molodets [167]3 years ago

5 0

Answer:

hence option A is correct

Explanation:

heat required from -9°C to 0°C ice = mass × specific heat of ice ×change in temperature

heat required from -9°C to 0°C ice = 7×2100×9 =132300 J =0.1323 MJ

( HERE SPECIFIC HEAT OF ICE IS A CONSTANT VALUE OF 2100

J/(kg °C )

heat required from 0°C ice to 0°C water = mass× specific heat of fusion of ice

= 7×3.36×10^5

= 2.352 × 10^6 J

= 2.352 MJ

TOTAL HEAT ENERGY REQUIRED = 0.1323 MJ +2.352 MJ

= 2.4843 MJ

hence option A is correct

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A body with the inertial

Andrews [41]

Answer:

Explanation:

Hi there,

To get started, recall the kinematic equations from either a textbook, equation sheet, etc. Kinematic equations are used when acceleration is <em>constant,</em> as stated in the prompt.

Best way to use kinematic equations is to see which variable you are looking for, then which variable is unknown to you and is not needed for that equation.

a) average velocity

Takes the form of:

$v_a_v_g=\frac{d_t_o_t_a_l}{t}=\frac{v+v_0}{2}$ this is the literal definition of average velocity; initial plus final divided by 2.

We know total displacement and total time elapsed, so we will use the middle form of the equation:

$v_a_v_g=\frac{1640m}{40s}=41 \ m/s$

b) the final velocity

We can still use the average velocity formula, as the other two equations that include final velocity have acceleration variable which is unknown as of now.

Solve for final velocity:

$v=(2v_a_v_g)-v_o = 2(41 \ m/s) - (8 m/s) = 74 m/s\\$ this makes sense, since a velocity later in time is higher than a velocity earlier in time. It is increasing with increasing time because of acceleration.

c) the acceleration

There are two equations that can be used to solve this, but we will use the less time-consuming one, but both produce same answer:

$a = \frac{v-v_0}{t_t_o_t_a_l} = \frac{(74-8)m/s}{40s} =1.65 m/s^{2}$

Notice, change in velocity over change in time, and acceleration is constant. When acceleration is constant, it models a linear function, and acc. is just slope!

Study well and persevere. If you liked this solution, hit Thanks or give a rating!

thanks,

3 0

3 years ago

The initial velocity of a micro van is 15 m/s. It gains a velocity of 40 ms in 10 seconds. Calculate the average velocity and ac

PSYCHO15rus [73]

Answer:

${ \bf{average \: velocity = \frac{15 + 40}{2}}} \\ = 27.5 \: {ms}^{ - 1} \\ { \bf{acceleration = \frac{v - u}{t} }} \\ = \frac{40 - 15}{10} \\ = 2.5 \: {ms}^{ - 2} \\ \\ { \tt{second \: qn : }} \\ { \bf{final \: velocity =u + at }} \\ v = 0 + (5 \times 10) \\ = 50 \: {ms}^{ - 1}$

5 0

2 years ago

A charged particle moving along the x-axis enters a uniform magnetic field pointing along the z-axis. Because of an electric fie

Furkat [3]

Answer:

Explanation:

Let the charge particle have charge equal to +q .

force due to electric field will be along the field that is along y - axis . To balance it force by magnetic force must be along - y axis. ( negative of y axis )

force due to magnetic field = q ( v x B ) , v is velocity and B is magnetic field.

F = q ( v i x B k ) , ( velocity is along x direction and magnetic field is along z axis. )

= (Bqv) - j

= - Bqv j

The force will be along - ve y - direction .

If we take charge as negative or - q

force due to electric field will be along - y axis .

magnetic force = F = -q ( v i x B k )

= + Bqv j

magnetic force will be along + y axis

So it is difficult to find out the nature of charge on the particle from this experiment.

5 0

3 years ago

The distiction between long and short term memory

RUDIKE [14]

Answer:

The main difference between short term and long term memory is that the short term memory stores data temporarily while the long term memory stores data permanently. Moreover, the short term memory is volatile while the long term memory is nonvolatile. Memory is the component in a computer that stores data and information.

Explanation:

4 0

3 years ago

A mass of 5kg accelerates at 3m/s/s, how much force was put on it?

goldfiish [28.3K]

Answer:

15N

Explanation:

According to Newton's Second Law of Motion

F = m*a

mass = m = 5Kg

acceleration = a = 3m/s^2

=> F = 5kg * 3m/s^2

=> F = 15 N

5 0

3 years ago

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