Answer:
a) about 20.4 meters high
b) about 4.08 seconds
Explanation:
Part a)
To find the maximum height the ball reaches under the action of gravity (g = 9.8 m/s^2) use the equation that connects change in velocity over time with acceleration.
In our case, the initial velocity of the ball as it leaves the hands of the person is Vi = 20 m/s, while thw final velocity of the ball as it reaches its maximum height is zero (0) m/s. Therefore we can solve for the time it takes the ball to reach the top:
Now we use this time in the expression for the distance covered (final position Xf minus initial position Xi) under acceleration:
Part b) Now we use the expression for distance covered under acceleration to find the time it takes for the ball to leave the person's hand and come back to it (notice that Xf-Xi in this case will be zero - same final and initial position)
To solve for "t" in this quadratic equation, we can factor it out as shown:
Therefore there are two possible solutions when each of the two factors equals zero:
1) t= 0 (which is not representative of our case) , and
2) the expression in parenthesis is zero:
Answer:
Explanation:
a )
Magnetic field inside solenoid B = μ₀ NI ,
μ₀ = 4π x 10⁻⁷ ; N is no of turns per meter length in solenoid and I is current B= 4π x 10⁻⁷ x 30 x 10² x 15
= .0565 T .
Force on each side of square loop = B i L
B is external magnetic field , i is current in loop and L is length of side
Force on each side of square loop = .0565 x .24 x 2 x 10⁻²
= 2.7 x 10⁻⁴ N .
b )
Torque on the loop = F x d
F is force on one side , d is distance between two sides , that is side of the square loop
= 2.7 x 10⁻⁴ x 2 x 10⁻² N.m
= 5.4 x 10⁻⁶ N.m .
A) a piece of wire
Explanation:
Radhika's mother is simply replacing piece of wire.
A fuse is made up of a thin strip of wire that melts when there is an over current.
- A fuse is electrical safety device in circuit that protects appliances from over current.
- The wire in a fuse has a high resistance and low melting point.
- When current is high, the resistance of the wire causes it to melt and break the circuit.
- In this way, appliances are protected from the harmful effect of the surge in voltage.
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Answer:
x(spring stretch)=1.74×10⁻³ meter
Explanation:
Given Data
l (length)=0.175 m
v (speed)= 3.86 m/s
x₁(stretch)=0.0140 m
x(spring stretch)=?
Solution
Centripetal force=Spring Constant
as
Spring force = gravitational force
75.17 mg of the radioactive substance will remain after 24 hours.
Answer:
Explanation:
Any radioactive substance will obey the exponential decay behavior. So according to this behavior, any radioactive substance will be decaying in terms of exponential form of disintegration constant and Time.
Disintegration constant is the rate of decay of radioactive elements. It can be measured using the half life time of the radioactive element .While half life time is the time taken by any radioactive element to decay half of its concentration. Like in this case, at first the scientist took 200 mg then after 17 hours, it got reduced to 100 g. So the half life time of this element is 17 hours.
Then Disintegration constant = 0.6932/Half Life time
Disintegration constant = 0.6932/17=0.041
Then as per the law of disintegration constant:
Here N is the amount of radioactive element remaining at time t and is the initial amount of sample, x is the disintegration constant.
So here, = 200 mg, x = 0.041 and t = 24 hrs.
N = 200 × =75.17 mg.
So 75.17 mg of the radioactive substance will remain after 24 hours.