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2 years ago

Need help today please

Physics

1 answer:

Eddi Din [679]2 years ago

3 0

6) True: the car is exerting an equal and opposite force on the truck

7) True: the astronaut can drift back by throwing the tool forward

8) True: the bug exerts an equal and opposite force on you

9) Second Law

Explanation:

This problem can be solved by applying Newton's third law of motion, which states that:

"When an object A exerts a force (action) on another object B, then object B exerts an equal and opposite force (reaction) on object A"

In this problem, we can identify the car and the truck as object A and object B. Here we are told that the truck is exerting a force on the car: therefore, according to Newton's third law, the car is also exerting an equal and opposite force on the truck.

Therefore, the statement is true.

This problem can be also solved by thinking in terms of the Newton's third law of motion.

In fact, at the beginning the astronaut is drifting away from the space station. When he throws away the tool, in the forward direction (away from the space station), he exerts a force on the tool: we can identify this force as the action force, and its direction is away from the space station.

As a result, according to Newton's third law, the tool will also exert a reaction force (equal and opposite) on the astronaut: therefore, the force exerted by the tool on the astronaut is toward the space station, and therefore the astronaut will be pushed back towards the station.

Therefore, the statement is true.

Again, this problem can also be explained using Newton's third law.

In fact, the moment you step on the bug, your foot exerts a force (the action force) on the bug, pushing downward.

As a result, according to Newton's third law, the bug exerts back on you an equal and opposite force (upward). The reason you don't feel this force at all is that your mass is much larger than that of the bug, therefore your acceleration is negligible.

Therefore, the statement is true.

This problem can be explained by using Newton's second law, which states that the net force acting on an object is equal to the product between its mass and its acceleration. Mathematically:

$F=ma$

where

F is the net force

m is the mass

a is the acceleration

In this problem, the ball slows down as it crosses the field: this means that it has an acceleration (more precisely, a negative acceleration). According to the law, this means also that there is a net, unbalanced force acting on it, in the direction opposite to the motion of the ball. In fact, this force is the force of friction between the ball and the surface.

Learn more about Newton laws of motion:

brainly.com/question/11411375

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#LearnwithBrainly

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Which are reactions that release energy? endothermic reactions exothermic reactions decomposition reactions

DochEvi [55]

Exothermic reactions are reactions that release energy.
Hope that helped you.

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3 years ago

A hollow plastic sphere is held below the surface of a fresh-water lake by a cord anchored to the bottom of the lake. The sphere

Naya [18.7K]

Answer: a) B = 6811N

b) m = 603.2kg

c) 86.8%

Explanation: Buoyant force is a force a fluid exerts on a submerged object.

It can be calculated as:

$B=\rho_{fluid}.V_{obj}.g$

where:

$\rho_{fluid}$ is density of the fluid the object is in;

$V_{obj}$ is volume of the object;

g is acceleration due to gravity, is constant and equals 9.8m/s²

a) For the hollow plastic sphere, density of water is 1000kg/m³:

$B=10^{3}.0.695.9.8$

B = 6811N

b) Anchored to the bottom, the forces acting on the sphere are Buoyant, Tension and Force due to gravity:

B = T + $F_{g}$

B = T + mg

mg = B - T

$m=\frac{B - T}{g}$

Calculating:

$m=\frac{6811 - 900}{9.8}$

m = 603.2kg

c) When the shpere comes to rest on the surface of the water, there are only buoyant and gravity acting on it:

B = m.g

$\rho_{w}.V_{sub}.g=m.g$

$V_{sub}=\frac{m}{\rho_{w}}$

$V_{sub}=\frac{603.2}{1000}$

$V_{sub}$ = 0.6032m³

Fraction of the submerged volume is:

$\frac{V_{sub}}{V_{obj}}$ = $\frac{0.6932}{0.695}$ = 0.868

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2 years ago

explain the fleming left-hand rule with the diagram and what will the direction of the induced current in the figure if the magn

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1 year ago

A 6,000 kg train car is moving to the right at 10 m/s and connects to a 4,000-kg train car that wasn't moving. What is the veloc

vredina [299]

1) The final velocity of the two trains is 6 m/s to the right

2) It is an inelastic collision

Explanation:

We can solve this problem by using the law of conservation of momentum: in fact, in absence of external forces, the total momentum of the two trains must be conserved before and after the collision.

Therefore we can write:

$p_i = p_f\\m_1 u_1 + m_2 u_2 = (m_1+m_2)v$

where:

$m_1 = 6,000 kg$ is the mass of the first train

$u_1 = 10 m/s$ is the initial velocity of the first train

$m_2 = 4,000 kg$ is the mass of the second train

$u_2 = 0$ is the initial velocity of the second train (initially at rest)

$v$ is the final combined velocity of the two trains

Solving the equation for v, we find the final velocity of the two trains:

$v=\frac{m_1 u_1 + m_2 u_2}{m_1+m_2}=\frac{(6000)(10)+0}{6000+4000}=6 m/s$

There are two types of collisions:

Elastic collision: in an elastic collision, both the total momentum and the total kinetic energy of the system are conserved
Inelastic collision: in an inelastic collision, only the total momentum is conserved, while the total kinetic energy is not (part of it is converted into thermal energy due to internal frictions)

To verify what type of collision is this, we can compare the total kinetic energy before and after the collision:

Before:

$K=\frac{1}{2}m_1 u_1^2 = \frac{1}{2}(6000)(10)^2=300,000 J$