When lifting weights, arch your lower back for extra strength. Is this true?

"A block of metal weighs 40 N in air and 30 N in water. What is the buoyant force on the block due to the water? The density of

Alja [10]

Answer:

buoyant force on the block due to the water= 10 N

Explanation:

We know that

buoyant force(F_B) on a block= weight of the block in air (actual weight) - weight of block in water.

Given:

A block of metal weighs 40 N in air and 30 N in water.

F_B = 40-30= 10 N

therefore, buoyant force on the block due to the water= 10 N

6 0

2 years ago

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A large crate of mass m is placed on the back of a truck but not tied down. As the truck accelerates forward with an acceleratio

Andrew [12]

"Force of friction between the crate and the floor of the truck" is the one force among the choices given in the question that <span>causes the crate to accelerate forward. The correct option among all the options that are given in the question is the third option or option "c". I hope the answer helps you.</span>

4 0

3 years ago

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The engine in an imaginary sports car can provide constant power to the wheels over a range of speeds from 0 to 70 miles per hou

Inessa05 [86]

Answer:

a) 4.40 s

b) 2.20 s

Explanation:

Given parameters are:

At constant power ,

initial speed of the car, $v_0=0$

final speed of the car, $v=32$ mph

At full power,

initial speed of the car, $v_0=0$

final speed of the car, $v=64$ mph

a)

At constant power, $KE = \frac{1}{2} mv^2$

At full power, $KE = \frac{1}{2} m(2v)^2$

So $KE_f = 4KE_i$

So, time to reach 64 mph speed is 4 times more than the initial time

$t = 4*1.10 =4.40$ s

b)

$v=v_0+at\\a=\frac{v-v_0}{t}=\frac{32-0}{1.1/3600}=104727.27$ $miles/hours^2$

For final 64 mph speed,

$v=v_0+at\\t=\frac{v-v_0}{a}=\frac{64-0}{104727.27} = 6.111*10^{-4}$ $hours$ = $6.111*10^{-4}*3600=2.20$ s

7 0

3 years ago

PLEASE HELP!!! GIVING BRAINLIEST!! ill also answer questions that you have posted if you answer this correctly!!!! (40pts)

Soloha48 [4]

Answer:

Newton's second law: F=ma.

Force = mass x acceleration

This basically means, that the more massive something is, and the faster it is going, the more force the object will have.

So, the factors that can be used to find acceleration are:

F=ma

a=F/m

So, we see that the correct answer is A, mass and force.

Let me know if this helps!

8 0

2 years ago

How much is the velocity of a body when it travels 600m in 5 minutes?( with the full process)

Tcecarenko [31]

Its average speed, pretending that it traveled at a constant speed, is

v = s / t

= 600 m

5 x 60 s

= 2 m/s

but to be a velocity it needs a direction as well as a speed.

( Sorry. Can’t find a division line to put between the 600 m and the 5 x 60 s )

6 0

3 years ago