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3 years ago

A physics teacher performed a demonstration for a science class by pulling a crate across the floor

Physics

1 answer:

nika2105 [10]3 years ago

3 0

Answer:

An opposing force caused by friction produced a lower acceleration than calculated.

Explanation:

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7. A block of copper of unknown mass has an initial temperature of 65.4oC. The copper is immersed in a beaker containing 95.7g o

dolphi86 [110]

Answer:

37.34372 kg

Explanation:

m = Mass

$\Delta T$ = Change in temperature

1 denotes water

2 denotes copper

c = Heat capacity

Heat is given by

$Q=mc\Delta T$

In this case the heat transfer will be equal

$m_1c_1\Delta T_1=m_2c_2\Delta T_2\\\Rightarrow m_2=\frac{m_1c_1\Delta T_1}{c_2\Delta T_2}\\\Rightarrow m_2=\frac{95.7\times 4.18(24.2-22.7)}{0.39(65.4-24.2)}\\\Rightarrow m_2=37.34372\ kg$

Mass of copper block is 37.34372 kg

5 0

3 years ago

After asking a question, a scientist can form a(n) , which is an idea that may be proved or disproved by an experiment.

DochEvi [55]

Answer:

When scientists have a question, they form a hypothesis, which is an idea that may be proved or disproved by an experiment.

6 0

3 years ago

Read 2 more answers

A force of 10. N toward the right is exerted on a wooden crate initially moving to the right on a horizontal wooden floor. the c

Artyom0805 [142]

1) 5 N

The crate is initially moving, so we must calculate the force of kinetic friction, which is given by:

$F_f = \mu_k mg$

where

$\mu_k=0.2$ is the coefficient of friction between the crate (made of wood) and the floor (made of wood). The coefficient of kinetic friction between wood and wood is about 0.2.

$mg=25 N$ is the weight of the crate

Substituting the numbers into the formula, we find

$F_f=(0.2)(25 N)=5 N$

2) 5 N

There are two forces acting on the crate along the horizontal direction:

- The force that pushes the crate toward the right, of magnitude $F=10 N$

- The force of friction, which acts in the opposite direction (so, towards the left), of magnitude $F_f = 5 N$

Since the two forces are in opposite directions, the net force is given by their difference:

$F_{net}=F-F_f = 10 N-5 N=5 N$

3) Yes

The crate is accelerating. In fact, according to Second Newton's Law:

$F_{net}=ma$ (1)

where Fnet is the net force on the crate, m is its mass, a is its acceleration. We can immediately see that since Fnet is not zero, the acceleration is also non-zero, so the crate is accelerating.

We can even calculate the magnitude of the acceleration. In fact, the mass of the crate is given by:

$m=\frac{Weight}{g}=\frac{25 N}{9.8 m/s^2}=2.55 kg$