To hoist himself into a tree, a 72.0-kg man ties one end of a nylon rope around his waist and throws the other end over a branch
of the tree. He then pulls downward on the free end of the rope with a force of 358 N. Neglect any friction between the rope and the branch, and determine the man’s upward acceleration.
1 answer:
Answer:
acceleration a= 0.1344 m/sec^2
Explanation:
Given
mass of the object m= 72 kg
Force applied with help of rope= 358 N
Acceleration due to gravity= 9.81 m/sec^2
Since there is no force acting on the person and rope
then T=F
and from the FBD we can write
2T- mg= ma ,or
2F- mg= ma
now putting the values we get
on calculating we get acceleration a= 0.1344 m/sec^2
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Answer:
0.0365 A
Explanation:
Data provided in the question:
Peak value of the voltage, V = 17.0 volts
Resistance of the resistor, r = 329.0 ohm
Now,
The rms current () is given by the relation as:
on substituting the respective values, in the equation, we get
or
= 0.0365 A
Hence, the rms current is 0.0365 A
Answer:
F = 2 × 10⁻³ N
Explanation:
Given:
frequency, f = 2400 MHz
Height, h = 25cm = 0.25 m
Area of the base, A = 30 cm x 30 cm = 900 cm² = 0.09 m²
Energy of the microwave, E = 0.50 mJ = 0.5 x 10⁻³ J
Now, the time taken by the wave from top to the base, t = h/c
here, c is the speed of the light
thus,
t = 0.25/(3 x 10⁸) = 8.33 x 10⁻¹⁰ s
The radiation pressure = Intensity/c
now, the intensity is given as:
I = Power/ area
also,
Power = Energy/ time = 0.5 x 10⁻³ J/8.33 x 10⁻¹⁰ s = 600000 W
thus,
I = 600000 W/ 0.09 m² = 6666666.6 W/m²
substituting the value in the formula for pressure due to radiation, we have
= 6666666.6 W/m²/(3 x 10⁸)
also
pressure = Force/ area
thus,
Force/ area = 6666666.6 W/m²/(3 x 10⁸)
or
Force (F) = (6666666.6 W/m² × 0.09 m²)/(3 x 10⁸)
or
F = 2 × 10⁻³ N