In a block and tackle, some friction in the pulleys will reduce the mechanical advantage of the machine. To include friction in a calculation of the mechanical advantage of a block and tackle, divide the weight of the object being lifted by the weight necessary to lift it.
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B.) <span>The range of all electromagnetic radiation is known as the "Electromagnetic Spectrum"
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Specific heat capacity= heat energy/mass×temperature rise
962°C - 20°C = 942K
Heat energy (Eh) = 239 × 1.55 × 942
Eh= 348963.9J
shc of Ag: 238.6 J/kg-K
m of Ag: 1.55kg
Answer:
2.24 m/s
Explanation:
resolving force of 29.2 N in x component
Fx = 29.2 cos 57.7
Fx = 15.6N
as force of friction is 12.7 N hence net force which produces acceleration is
15.6-12.7=2.9 N
by Newton 's law a=f/m
a= 2.9/6.87=0.422 m/s^2
now equation of motion is
v^2= U^2+2as
= 0^2+2(.422)(5.93)
v^2=5.00
v=2.24 m/s
Answer:
0.405 seconds
Explanation:
Consider the amount of time it takes the block to fall from 53 m up to 14 m above the ground; then consider the amount of time it takes the block to fall from 53 m up to 2 m above the ground.
First, d = (1/2) gt^2 or t= ( 2 d / g)^1/2
= ( 2 × 39 / 9.8)^1/2 = 2.8212 seconds
Then, to fall from 53 down to 2 meters...
d = (1/2) gt^2 or t= ( 2 d / g)^1/2
= ( 2 * 51/ 9.8 )^1/2 = 3.2262 seconds
So the amount of time it takes for the block to fall from 14 m upto 2 m above the ground
3.2262 - 2.8212 = 0.405 seconds
this is how much time there is from when the man sees the block until it hits him. Not much time...
