Answer:
initial: 1654.6 J, final: 0 J, change: -1654.6 J
Explanation:
The length of the slide is
L = 8.80 ft = 2.68 m
So the height of the child when he is at the top of the slide is (with respect to the ground)
The potential energy of the child at the top is given by:
where
m = 63.0 kg is the mass of the child
g = 9.8 m/s^2 is the acceleration due to gravity
h = 1.13 m
Substituting,
At the bottom instead, the height is zero:
h = 0
So the potential energy is also zero: U = 0 J.
This means that the change in potential energy as the child slides down is
Answer:
number 4
Explanation:
The reflection of light happens when the light bounces off the reflecting surface. That is described by the last (bottom) schematics.
Therefore, select answer number 4.
Work= force x displacement :)
<span>3.92 m/s^2
Assuming that the local gravitational acceleration is 9.8 m/s^2, then the maximum acceleration that the truck can have is the coefficient of static friction multiplied by the local gravitational acceleration, so
0.4 * 9.8 m/s^2 = 3.92 m/s^2
If you want the more complicated answer, the normal force that the crate exerts is it's mass times the local gravitational acceleration, so
20.0 kg * 9.8 m/s^2 = 196 kg*m/s^2 = 196 N
Multiply by the coefficient of static friction, giving
196 N * 0.4 = 78.4 N
So we need to apply 78.4 N of force to start the crate moving. Let's divide by the crate's mass
78.4 N / 20.0 kg
= 78.4 kg*m/s^2 / 20.0 kg
= 3.92 m/s^2
And you get the same result.</span>
Answer:
1.) U = 39.2 m/s
2.) t = 4s
Explanation: Given that the
height H = 78.4m
The projectile is fired vertically upwards under the acceleration due to gravity g = 9.8 m/s^2
Let's assume that the maximum height = 78.4m. And at maximum height, final velocity V = 0
Velocity of projections can be achieved by using the formula
V^2 = U^2 - 2gH
g will be negative as the object is moving against the gravity
0 = U^2 - 2 × 9.8 × 78.4
U^2 = 1536.64
U = sqrt( 1536.64 )
U = 39.2 m/s
The time it takes to reach its highest point can be calculated by using the formula;
V = U - gt
Where V = 0
Substitute U and t into the formula
0 = 39.2 - 9.8 × t
9.8t = 39.2
t = 39.2/9.8
t = 4 seconds.
