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3 years ago

If a ball is rolling across a floor at a constant speed is it accelerating

Physics

1 answer:

KATRIN_1 [288]3 years ago

8 0

You already told us that its speed is constant. That's one part of acceleration.

The other part of acceleration is the direction it's moving.

If it's rolling in a straight line, then there's no acceleration.

If it's curving left or right, then that's acceleration.

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A box of mass 60 kg is at rest on a horizontal floor that has a static coefficient of friction of 0.6 and a kinetic coefficient

gavmur [86]

Answer:

a) The minimum force required to start moving the box is 352.86 N

b) i) The friction force for the box in motion is 147.025 N

ii) The acceleration of box is 4.21625 m/s²

Explanation:

The parameters of the box at rest and the floor are;

The mass of the box = 60 kg

The static coefficient friction of the floor = 0.6

The kinetic coefficient friction of the floor = 0.25

Frictional force = Normal force × Friction coefficient

For an horizontal floor and the box laying on the floor, we have;

The normal force = The weight of the box = Mass of the box × Acceleration due to gravity, g

The acceleration due to gravity, g = 9.81 m/s²

The weight of the box = 60 × 9.81 = 588.6 N

a) The static coefficient gives the frictional force observed by the box and which must be surpassed to bring about motion

Therefore;

The minimum force required to start moving the box = The static frictional force = Weight of the box × The static coefficient of friction

The minimum force required to start moving the box = 588.1 × 0.6 = 352.86 N

The minimum force required to start moving the box = 352.86 N

b) i) When an horizontal force of 400 N is applied, the applied force is larger than the static friction force, and the box will be in motion with the kinetic coefficient of friction being the source of friction

The friction force for the box in motion = 588.1 × 0.25 = 147.025 N

ii) The force, F with the box is in motion, is given as follows;

F = Mass of box × Acceleration of box, a = Applied force - Kinematic friction force

F = 60 × a = 400 - 147.025 = 252.975 N

60 × a = 252.975 N

a = 252.975 N/(60 kg) = 4.21625 m/s²

Acceleration of box, a = 4.21625 m/s².

6 0

2 years ago

Emily sprains her ankle on her way home from school. Her mom suggests she use an “instant cold pack” to reduce the swelling. Whe

tresset_1 [31]

<span>In energy transfer, happens from one object to another without changing its form. For example, when you fill a pot of water and sit it on the stove, the water continues to heat until you turn it off. While in a energy transformation, the energy changes forms such as Chemical, kinetic.</span>

4 0

3 years ago

You stand on a bridge above a river and drop a rock into the water below from a height of 25 m. (Assume no air resistance)

Ilia_Sergeevich [38]

PART a)

here when stone is dropped there is only gravitational force on it

so its acceleration is only due to gravity

so we will have

$a = g = 9.8 m/s^2$

Part b)

Now from kinematics equation we will have

$y = v_i t + \frac{1}{2} at^2$

now we have

y = 25 m

so from above equation

$25 = 0 + \frac{1}{2}(9.8 )t^2$

$t = 2.26 s$

Part c)

If we throw the rock horizontally by speed 20 m/s

then in this case there is no change in the vertical velocity

so it will take same time to reach the water surface as it took initially

So t = 2.26 s

Part D)

Initial speed = 20 m/s

angle of projection = 65 degree

now we have

$v_x = vcos\theta$

$v_x = 20 cos65 = 8.45 m/s$

$v_y = vsin\theta$

$v_y = 20 sin65 = 18.13 m/s$

PART E)

when stone will reach to maximum height then we know that its final speed in y direction becomes zero

so here we can use kinematics in Y direction

$v_f - v_y = at$

$0 - 18.13 = (-9.8) t$

$t = 1.85 s$

so it will take 1.85 s to reach the top

5 0

2 years ago

A football player kicks a 0.94 kg football with a force of 2.4 N.

Artyom0805 [142]

2.6m/s²

Explanation:

Given parameters:

Mass of football = 0.94kg

Force on ball = 2.4N

Unknown:

The acceleration of the ball = ?

Solution:

According to Newton's second law of motion "the net force on a body is the product of its mass and acceleration".

Net force = mass x acceleration

Make acceleration the subject of the expression;

Acceleration = $\frac{net force}{mass}$

Acceleration = $\frac{2.4}{0.94}$ = 2.6m/s²

learn more:

Acceleration brainly.com/question/3820012

#learnwithBrainly

6 0

3 years ago

Read 2 more answers

ArbitrLikvidat [17]

Answer:

D) Number of electrons.

Explanation:

Elements in the same group on the periodic table has the same number of electrons. These electrons are those involved in bonding with other atoms to form compounds.

3 0

2 years ago