Answer: a and d
Explanation: A.) the power lines themselves
B.) the wooden pole that supports the lines
C.) the rubber soles on the worker’s boots
D.) the metal tools the worker uses
E.) the wooden ladder leaning against the lines
Answer:
Explanation:
fundamental frequency, f = 250 Hz
Let T be the tension in the string and length of the string is l ans m be the mass of the string initially.
the formula for the frequency is given by
.... (1)
Now the length is doubled ans the tension is four times but the mass remains same.
let the frequency is f'
.... (2)
Divide equation (2) by equation (1)
f' = √2 x f
f' = 1.414 x 250
f' = 353.5 Hz
Force = (mass) x (acceleration)
Force = (18 kg) x (3 m/s²) = 54 newtons
As long as you continue pushing the cart with 54 newtons of force,
it will accelerate at 3 m/s².
At the instant you release it, or keep your hands on it but stop pushing,
it will stop accelerating. It'll continue forward at the speed it had when
the 54 newtons of force stopped.
Answer:


Explanation:
Height Of the watermelon when it is dropped is given as

time of fall under gravity

now if water melon start from rest then we have

acceleration due to gravity for watermelon

now we need to find the final speed of watermelon

so we will have


Answer:
160N
Explanation: When 80kg mass is one group . It's reaction force acting on a ground.
Weight of the object = 80*10
= 800 N
Here we are given cofficient of static friction its 0.2. It should be smaller than 1
Friction force = Reaction * Friction Cofficient
Reaction = 800N ( Considering Vertical Equilibrium )
F = 800* 0.2
F = 160N