Speed of the projectile at its maximum height is only along horizontal direction
so at highest point

now when he is at half of the maximum height the speed will be in x and y direction both

here it is given that




also we know that

here we know that maximum height is given as



now from above


also we know that angle of projection is


so angle is


Answer:
(B) Resistor only
Explanation:
Alternating Current: These are currents that changes periodically with time.
An LRC Ac circuit is an AC circuit that contains a Resistor, a capacitor and an inductor, connected in series.
In a purely resistive circuit, current and voltage are in phase.
In a purely capacitive circuit, the current leads the voltage by π/2
In a purely inductive circuit, the current lags the voltage by π/2.
Therefore when a alternating current is set up in LRC circuit, in the resistor, the current and the voltage are in phase.
The right option is (B) Resistor only.
Answer:
v = 0.41 m/s
Explanation:
- In this case, the change in the mechanical energy, is equal to the work done by the fricition force on the block.
- At any point, the total mechanical energy is the sum of the kinetic energy plus the elastic potential energy.
- So, we can write the following general equation, taking the initial and final values of the energies:

- Since the block and spring start at rest, the change in the kinetic energy is just the final kinetic energy value, Kf.
- ⇒ Kf = 1/2*m*vf² (2)
- The change in the potential energy, can be written as follows:

where k = force constant = 815 N/m
xf = final displacement of the block = 0.01 m (taking as x=0 the position
for the spring at equilibrium)
x₀ = initial displacement of the block = 0.03 m
- Regarding the work done by the force of friction, it can be written as follows:

where μk = coefficient of kinettic friction, Fn = normal force, and Δx =
horizontal displacement.
- Since the surface is horizontal, and no acceleration is present in the vertical direction, the normal force must be equal and opposite to the force due to gravity, Fg:
- Fn = Fg= m*g (5)
- Replacing (5) in (4), and (3) and (4) in (1), and rearranging, we get:


- Replacing by the values of m, k, g, xf and x₀, in (7) and solving for v, we finally get:

1) B. Energy is the ability to do work
2) C. Energy is conserved, it just goes from one form to another.
3) Work = Force x displacement
= 300 x 100 = 30,000 Joules
4) leaning a brick because no displacement is taking place.
5) They change the amount/strength or direction of the force needed.
6) Less force is needed and applied over a longer distance.
7) Heat is the flow of thermal energy from one object to another.
Answer:
<h3>1.43m/s²</h3>
Explanation:
According to newtons second law.
F = mass * acceleration
If the doll has a mass of 0.2 kg, and the robot has a mass of 0.5 kg, the resulting mass will be 0.7kg
Force applied = 1N
acceleration = Force/mass
Substitute the values and get acceleration
acceleration = 1/0.7
acceleration = 1.43m/s²
Hence the magnitude of the acceleration of the robot is 1.43m/s²