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2 years ago

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A 3kg book falls from a shelf. If it lands with a speed of 4.8 m/s, from what height did it fall? A. 28.8 m , B. 1.2 m , C. 0.6

m , D. 14.1 m

1 answer:

Irina-Kira [14]2 years ago

7 0

The correct answer is B. 1.2 m (apex)

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Changes in the object's momentum (answer D)

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How many layers does the world have?

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A solid metal object hangs from a force sensor by a thread in the open air, and the actual weight is measured to be 0.71 N. Then

Alexeev081 [22]

Answer:

The apparent weight of the object is 0.465 N.

Explanation:

Given that,

Weight = 0.71 N

Water level = 50 mL

object inserted = 75 mL

We need to calculate the volume of solid

Using formula of volume

$V=25\ ml = 25\times10^{-6}\ m^3$

We need to calculate the buoyancy force

Using formula of buoyancy force

$F'= V\rho g$

Put the value into the formula

$F'=25\times10^{-6}\times1000\times9.8$

$F'=0.245\ N$

We need to calculate the apparent weight of the object

Using formula of apparent weight

$W=F-F'$

Put the value into the formula

$W=0.71-0.245$

$W=0.465\ N$

Hence, The apparent weight of the object is 0.465 N.

5 0

2 years ago

A 1.3 kg ball drops vertically onto a floor, hitting with a speed of 21 m/s. It rebounds with an initial speed of 9.8 m/s. (a) W

Anarel [89]

Answer:

a) Impulse(J)=40.04 kg.m/s

b)F=2566.66 N

Explanation:

Given that

$V_1=21 m/s,V_2=9.8m/s$

We know that impulse(J) impulse is a vector quantity

$J=P_2-P_1$

We know that P=mV

So $J=m(V_2-V_1)$

Now by putting the values

J=1.3(9.8-(-21))

So impulse(J)=40.04 kg.m/s

Force is given as

$F=\dfrac{dP}{dt}$

or we can say that

$F=m\left(\dfrac{v_2-V_1}{dt}\right)$

So $F=\dfrac{40.04}{0.0156}$

F=2566.66 N

3 0

2 years ago