Answer:
<h2>a) t = 4</h2>
Explanation:
In projectile the time taken by an object to reach its maximum height is the maximum time (tmax).
tmax = Usin
/g
U = velocity of the ball
= angle of projection = 90° (vertical velocity)
g = acceleration due to gravity = 9.8m/s²
tmax = Usin90°/9.8
tmax = U/9.8
T the maximum height U = Uy = 39.2 m/s²
tmax = 39.2/9.8
tmax = 4secs
To calculate the time at which the ball will have an horizontal velocity, we will use the same formula but will be 0° in this case
If Ux = Ucos
8 = Ucos0
U = 8m/s
Since t = Usin/g
t = 8sin0/9.8
t = 0sec
Answer:
Explanation:
A ball is thrown vertically upward with a certain Kinetic Energy in the absence of air resistance and while returning it experiences air resistance.
Air resistance causes the ball to lose its kinetic energy as it provides resistance which will convert some of its kinetic energy to heat energy.
So in a way total energy is conserved but not kinetic energy as some portion of it is lost in the form of heat.
I'll assume that the chair has four legs.
Since the chair weights 3.7 kg by itself, it will weigh (79+3.7)=82.7 kg with the person sitting on it. And each of the chair's legs will take about (82.7/4)=20.675 kg.
Each leg touches the floor in a circle with 1.3cm diameter. The area of that circle is about (3.14*(1.3/2)^2)=1.327 cm^2.
Pressure is measured by force per area. So, the pressure from each leg is about 20.675kg / 1.327cm^2. That simplifies to 15.58 kg/cm^2.
Answer:
<em>The end of the ramp is 38.416 m high</em>
Explanation:
<u>Horizontal Motion
</u>
When an object is thrown horizontally with an initial speed v and from a height h, it follows a curved path ruled by gravity.
The maximum horizontal distance traveled by the object can be calculated as follows:
If the maximum horizontal distance is known, we can solve the above equation for h:
The skier initiates the horizontal motion at v=25 m/s and lands at a distance d=70 m from the base of the ramp. The height is now calculated:
h= 38.416 m
The end of the ramp is 38.416 m high
Answer: Friction also prevents an object from starting to move, such as a shoe placed on a ramp. When friction acts between two surfaces that are moving over each other, some kinetic energy is transformed into heat energy. Friction can sometimes be useful.
Explanation:
