A cow’s mass is 410 kg and a car’s mass is 565 kg. What is the difference between their weights?

A 74.9 kg person sits at rest on an icy pond holding a 2.44 kg physics book. he throws the physics book west at 8.25 m/s. what i

never [62]

Answer:

The recoil velocity is 0.2687 m/s.

Explanation:

∵ The person is sitting on an icy surface , we can assume that the surface is frictionless.

∴ There is no force acting acting on the person and book as a system in horizontal direction.

Hence , momentum is conserved for this system in horizontal direction of motion.

If 'i' and 'f' be the initial and final states of this system , then by principle of conservation of momentum(p) -

$p_{i}$ = $p_{f}$

System initially is at rest

∴ $p_{i}$ =0

∴ From the above 2 equations

$p_{f}$ =0

We know that ,

Momentum(p)=Mass of the body(m)×velocity of the body(v)

Let $m_{1}$ and $m_{2}$ be the mass of the person and the book respectively and $v_{1}$ and $v_{2}$ be the final velocities of the person and book respectively.

∴ $p_{f}$ = $m_{1}$ $v_{1}$ + $m_{2}$ $v_{2}$ =0

From the question ,

$m_{1}$ = 74.9 kg

$m_{2}$ = 2.44 kg

$v_{2}$ = 8.25 m/s

Substituting these values in the above equation we get ,

(74.9 × $v_{1}$ )+ (2.44×8.25) = 0

∴ $v_{1}$ = - 0.2687 m/s (Negative sign suggests that the motion of the person is opposite to that of the book)

∴ The recoil velocity is 0.2687 m/s.

4 0

2 years ago

A tin can whirled on the end of a string moves in a circle because

Ilya [14]

Answer:

There is an inward force acting on the can

Explanation:

This inward force is known as Centripetal force and it is responsible for making the can whirl on the end of a string in circle and it is also directed towards the center around which the can is moving.

8 0

2 years ago

If a satellite is orbiting the Earth in elliptical motion, then it will move _______________ (slowest, fastest) when its closest

AVprozaik [17]

Answer:fastest,same,slow down,opposite,slow

Explanation:

8 0

1 year ago

A chair of mass 12.0 kg is sitting on the horizontal floor; the floor is not frictionless. You push on the chair with a force F

Tanya [424]

Answer: Normal force, N = 141.64 Newton

Explanation:

All the forces acting on the system and described in free body diagram are:

1) gravitational pull in downward direction

2) Normal force in upward direction

3) External force of 40 N acting at an angle of 37° with the horizontal can be resolved in two rectangular components:

i) F Cos 37° along the horizontal plane in forward direction and

ii) F Sin 37° along the vertical plane in downward direction

Applying the Newton's second law, net forces in the vertical plane are:

Net force, f = N - (mg + F Sin 37°)

As there is no acceleration in the vertical plane hence, net force f = 0.

So,

N - (mg + F Sin 37°) = 0

Adding (mg + F Sin 37°) both the sides in above equation, we get

N = mg + F Sin 37°

N = 12 $\times$ 9.8 + 40 $\times$ 0.601 because (Sin 37° = 0.601)

N = 117.6 + 24.04

N = 141.64 Newton

3 0

2 years ago

Exercise 2.4.6: Suppose you wish to measure the friction a mass of 0.1 kg experiences as it slides along a floor (you wish to fi

JulijaS [17]

Answer:

b = 0.6487 kg / s

Explanation:

In an oscillatory motion, friction is proportional to speed,

fr = - b v

where b is the coefficient of friction

when solving the equation the angular velocity has the form

w² = k / m - (b / 2m)²

In this exercise we are given the angular velocity w = 1Hz, the mass of the body m = 0.1 kg, and the spring constant k = 5 N / m. Therefore we can disperse the coefficient of friction

let's call

w₀² = k / m

w² = w₀² - b² / 4m²

b² = (w₀² -w²) 4 m²

Let's find the angular velocities

w₀² = 5 / 0.1

w₀² = 50

w = 2π f

w = 2π 1

w = 6.2832 rad / s

we subtitute

b² = (50 - 6.2832²) 4 0.1²

b = √ 0.42086

b = 0.6487 kg / s

8 0

2 years ago