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Marysya12 [62]
3 years ago
9

3. A 142 g baseball is thrown at a speed of 42.9 m/s. What is the kinetic energy of the baseball at this moment?

Physics
1 answer:
krok68 [10]3 years ago
8 0
Kinetic energy=1/2mv^2
=1/2(142*10^-3)(42.9)^2=130.6=131J
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A 0.500 kg ball is dropped from rest at a point 1.20 m above the floor. The ball rebounds straight upward to a height of 0.700 m
KatRina [158]

To solve this problem we will apply the concepts related to energy conservation. With this we will find the speed before the impact. Through the kinematic equations of linear motion we will find the velocity after the impact.

Since the momentum is given as the product between mass and velocity difference, we will proceed with the velocities found to calculate it.

Part A) Conservation of the energy

mgh = \frac{1}{2} mv^2

v_1 = \sqrt{2gh}

v_1 = \sqrt{2(9.8)(1.20)}

v_1 = 4.84m/s

\therefore v_1 = -4.84/s \rightarrow \text{Negative direction downward}

Part B)  Kinematic equation of linear motion,

v_2^2 = u_0^2 +2a\Delta y

Here

v= 0 Because at 1.5m reaches highest point, so v=0

0 = u_2^2 +2(-9.8)(0.7)

u_2 = 3.7m/s

Therefore the velocity after the collision with the floor is 3.7m/s

PART C) Total change of impulse is given as,

J = P_2 -P_1

J = mU_2-mV_1

J = m(U_2-V_1)

J = (0.5)(3.7-(-4.84))

J = 4.27kg \cdot m/s \rightarrow \text{Upward because is positive}

6 0
4 years ago
An object with a mass of 2.0 kg accelerates 2.0 m/s2 when an unknown force is applied to it. What is the amount of the force?
MAXImum [283]

force is mass * acceleration  

so 2kg * 2m/s^2 = 4 N

5 0
4 years ago
You throw a stone upward from the top of a building at an angle of 25° to the horizontal and with an initial speed of 15 m/s. I
Alex787 [66]

Answer:

11.025 m

87.75 m

Explanation:

Time of flight(T) of a projectile = 2U(sin∅)/g

Where U = initial Velocity, g = acceleration due to gravity, ∅= angle of projection.

Make ∅ the subject of the the equation,

∅ = sin⁻¹[(T× g)/2U]

Where U = 15m/s, T= 3.0 s, g = 9.8 m/s²

∅ = sin⁻¹[(3 × 9.8)/(2×15)]

∅ = sin⁻¹(29.4/30)

∅= sin⁻¹(0.98) = 78.52°

Using the formula for maximum height of a projectile

H = U²sin²∅/2g

H = 15²(sin²78.52)/2 × 9.8

H = 225(0.98 × 0.98)/19.6

H = 216.09/19.6

H = 11.025 m

Range (R) = U²sin2∅/g

R = 15²sin(2×79.52)/9.8

R = 225(0.39)

R =87.75 m

∵ the building is = 11.025 m tall and the base of the building is 87.75m away from where the stone landed.

6 0
4 years ago
Select the correct answer.
Bumek [7]

Answer:

B. 2 Hours

Explanation:

If you are going 45 miles per hour, you will travel 45 miles in 1 hour. It will take you 2 hours to travel 90 miles at a speed of 45 miles per hour.

3 0
3 years ago
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What is the electric potential at a distance of 1.2 m from a 7.5 UC point charge?
grandymaker [24]

Answer:

A. 5.6x10^4

Explanation:

Big Brain

7 0
3 years ago
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