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2 years ago

April stands on a flat surface. If she has a mass of 72 kg, what is the normal force acting on her?

2 answers:

3 0

IF she is on or near the surface of Earth at the time, then ...

... Her WEIGHT is (mass) (gravity) = (72 kg) (9.8 m/s²) = 705.6 Newtons

... The surface under her feet exerts a normal force, upward,
against her feet.

... If the upward normal force is NOT 705.6 Newtons, then the
NET force on the bottom of her feet is not zero, and her feet are
accelerating, either up or down.

... But she is just standing there, not accelerating either up or down.

... Therefore, the NET force on the bottom of her feet must be zero.

... The normal force acting upward against her feet must be exactly
equal to her weight ... 705.6 Newtons.

statuscvo [17]2 years ago

3 0

706 N for apex users :)

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A stationary 1.67-kg object is struck by a stick. The object experiences a horizontal force given by F = at - bt2, where t is th

Usimov [2.4K]

Answer:

$v_{f}$ = 3289.8 m / s

Explanation:

This exercise can be solved using the definition of momentum

I = ∫ F dt

Let's replace and calculate

I = ∫ (at - bt²) dt

We integrate

I = a t² / 2 - b t³ / 3

We evaluate between the lower limits I=0 for t = 0 s and higher I=I for t = 2.74 ms

I = a (2,74² / 2- 0) - b (2,74³ / 3 -0)

I = a 3,754 - b 6,857

We substitute the values of a and b

I = 1500 3,754 - 20 6,857

I = 5,631 - 137.14

I = 5493.9 N s

Now let's use the relationship between momentum and momentum

I = Δp = m $v_{f}$ - m v₀o

I = m $v_{f}$ - 0

$v_{f}$ = I / m

$v_{f}$ = 5493.9 /1.67

$v_{f}$ = 3289.8 m / s

5 0

2 years ago

If a freely suspended vertical spring is pulled in downward direction and then released, which type of wave is produced in the s

larisa [96]

Answer:

longitudinal wave

Explanation:

it is perpendicular to the direction of the wave

3 0

2 years ago

Read 2 more answers

Two identical carts travel at the same speed toward each other, and then a collision occurs. The graphs show the momentum of eac

madam [21]

Explanation :

The interaction between two objects is termed as the collision. The collision can be of two types i.e. elastic collision and inelastic collision.

In this case, two identical carts travel at the same speed toward each other, and then a collision occurs. In an inelastic collision, the momentum before and after the collision remains the same but its kinetic energy gets lost.

After the collision, both the object sticks over each other and moves with one velocity.

Out of the given graph, the graph that shows a perfectly inelastic collision is attached. It shows that after the collision both the carts move with the same velocity.

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2 years ago

If you lived on Saturn, which planets would exhibit retrograde motion like that observed for Mars from Earth? (Select all that a

liberstina [14]

Answer:

a) Earth

b) Mercury

c) Neptune

Explanation:

All the planets move around the sun in eastward direction, but few planet have retrograde rotation i.e in westward direction. Retrograde motion is just an apparent change in the movement of planet which means it only seems as if the planet are rotating in opposite direction. Retrograde movement of planet like Saturn, Jupiter and mars is not real. Hence, if a person lives on Saturn, then following planets will exhibit retrograde motion

a) Earth

b) Mercury

c) Neptune

4 0

2 years ago

A radioactive isotope has a half-life of 2 hours. If a sample of the element contains 600,000 radioactive nuclei at 12 noon, how

storchak [24]

Answer: There will be 75258 nuclei left at 6 pm.

Explanation:

a) half-life of the radioactive substance:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

$t_{\frac{1}{2}}=\frac{0.69}{k}$