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Nutka1998 [239]
3 years ago
11

Brittany stands at rest on a skateboard. The combined mass of Brittany and the skateboard is 62 kg. Dave tosses a 3.7-kg pumpkin

to Brittany, and when she catches it, she and the skateboard begin to roll backward with a speed of 0.18 m/s.
What was the speed of the pumpkin?
Physics
1 answer:
Amiraneli [1.4K]3 years ago
5 0

Answer:

3.196 m/s

Explanation:

Parameters given:

Mass of Brittany and the skateboard, M = 62 kg

Mass of pumpkin, m = 3.7 kg

Initial speed of Brittany and the skateboard, U = 0 m/s

Final velocity of Brittany, the skateboard and the pumpkin, V = v = 0.18 m/s

We can solve this problem by applying the principle of conservation of momentum.

It states that the total final momentum of a system is equal to the total initial momentum of the system.

M*U + m*u = M*V + m*v

Where u is the initial velocity of the pumpkin.

Since the final velocity of Brittany and the skateboard is equal to the final velocity of pumpkin:

M*U + m*u = (M + m) *v

Solving this to get u:

(62 * 0) + (3.7 * u) = (62 + 3.7) * 0.18

0 + 3.7u = 65.7 * 0.18

3.7u = 11.826

u = 11.826 / 3.7

u = 3.196 m/s

The initial velocity of the pumpkin was 3.196 m/s.

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Answer:

The amount of work the factory worker must to stop the rolling ramp is 294 joules

Explanation:

The object rolling down the frictionless ramp has the following parameters;

The mass of the object = 10 kg

The height from which the object is rolled = 3 meters

The work done by the factory worker to stop the rolling ramp = The initial potential energy, P.E., of the ramp

Where;

The potential energy P.E. = m × g × h

m = The mass of the ramp = 10 kg

g = The acceleration due to gravity = 9.8 m/s²

h = The height from which the object rolls down = 3 m

Therefore, we have;

P.E. = 10 kg × 9.8 m/s² × 3 m = 294 Joules

The work done by the factory worker to stop the rolling ramp = P.E. = 294 joules

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A sound with an intensity greater than_____ dB can cause damage to human ears.
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3 years ago
In lecture, it was discussed measurements of mass, temperature, time, volume and length. which of these is not an si base unit (
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From the options provided in the question, the measurement which is not an SI base unit is volume.

<h3>What is SI base unit?</h3>

This is referred to as the standard and fundamental unit of measurement of various quantities or variables which is defined arbitrarily and not by combinations of other units.

Volume is a quantity which is derived from the combination of lengths in a  three-dimensional manner which is why the formula is length× breadth×height and the unit is cm³. This is gotten from the combination of the unit of length which is cm.

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A rifle bullet with mass 8.00g strikes and embeds itself in a block with mass 0.992kg that rests on a frictionless, horizontal s
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Answer:

block velocity   v = 0.09186 = 9.18 10⁻² m/s  and speed bollet   v₀ = 11.5 m / s

Explanation:

We will solve this problem using the concepts of the moment, let's try a system formed by the two bodies, the bullet and the block; In this system all scaffolds during the crash are internal, consequently, the moment is preserved.

Let's write the moment in two moments before the crash and after the crash, let's call the mass of the bullet (m) and the mass of the Block (M)

Before the crash

     p₀ = m v₀ + 0

After the crash

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    p₀ = p_{f}

    m v₀ = (m + M) v                    (1)

Now let's lock after the two bodies are joined, in this case the mechanical energy is conserved, write it in two moments after the crash and when you have the maximum compression of the spring

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   k = -F / x

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Let's calculate the speed

  v = √(k/m)   x

  v = √ (3/8.00)   0.15

  v = 0.09186 = 9.18 10⁻² m/s

This is the spped of  the  block  plus bullet rsystem right after the crash

We substitute calculate in equation  (1)

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  v₀ = v (m + M) / m

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