Answer:
1)
2)
Explanation:
<u>Projectile Motion</u>
When an object is launched near the Earth's surface forming an angle 
with the horizontal plane, it describes a well-known path called a parabola. The only force acting (neglecting the effects of the wind) is the gravity, which acts on the vertical axis.
The heigh of an object can be computed as
Where 
is the initial height above the ground level, 
is the vertical component of the initial velocity and t is the time
The y-component of the speed is
1) We'll find the vertical component of the initial speed since we have not enough data to compute the magnitude of 
The object will reach the maximum height when 
. It allows us to compute the time to reach that point
Solving for 
Thus, the maximum heigh is
We know this value is 8 meters
Solving for
Replacing the known values
2) We know at t=1.505 sec the ball is above Julie's head, we can compute
Answer:
1. The force of the shelf holding the book up.
Explanation:
The free body diagram of the book is as follows:
1 - The weight of the book towards downwards
2 - The normal force that the shelf exerts on the book towards upwards.
Since the book is at rest, these two forces are equal to each other and according to Newton's Third Law the reaction force to the force of gravity is equal but opposite to the weight of the book. This reaction force is the one that holds the book up on the shelf.
Answer:
B. 4 m/s
Explanation:
v=d/t
Running for 300 m at 3 m/s takes 100 seconds and running at 300 m at 6 m/s takes 50 seconds. 100 s + 50 s = 150 s (total time). Total distance is 600 m, so 600 m/ 150 s = 4 m/s.
Answer:
Option A is correct.
when it is used in a circuit. its terminal voltage will be less than 1.5 V.
Explanation:
The terminal voltage of the battery when it is in use in circuits drops lower than the 1.5 V rating given to it due to internal resistance.
All batteries give internal resistances when used in circuits. The internal resistance (though very small) is usually modelled as connected in series with the battery. It is due to some form of interference from the chemical makeup of the battery.
Normally, while the battery is fresh, the voltage (V) obtained at its terminals when connected in series with a resistor of resistance R is V = IR; where I is the current flowing in this circuit.
But once the interenal resistance (r) of the battery comes into play,
V = I₁ (r + R)
The current in the circuit evidently drops (that is I₁ < I) and V = (I₁r + I₁R)
The voltage across the terminals of the battery is no longer V but is now (V) × [R/(R+r)] which is less than the initial V and it reduces as the internal resistance, r, increases.
Hope this Helps!!!
<span>1.0344645 MJ
The minimum energy need is the potential energy of the car at the top of the ramp and is given by
mass*gravity*height
mass is known, gravity is assumed to be 9.81m/s^2 as it is on earth, and height must be calculated using trigonometry.
height=sin(9 degrees)*710m=111meters
so
potential energy = 950kg*111m*9.81m/s^2=1.0344645 MJ
Using the law of the conservation of energy we can assume that the energy expended to push the car up the incline was at least the potential energy gained by moving 111m against the pull of gravity.</span>
