1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
insens350 [35]
3 years ago
10

A truck, initially at rest, rolls down a frictionless hill and attains a speed of 20 m/s at the bottom. To achieve a speed of 40

m/s at the bottom, how many times higher must the hill be
Physics
1 answer:
Crank3 years ago
5 0

Answer:

To achieve the velocity of 40 m/sec height will become 4 times  

Explanation:

We have given initially truck is at rest and attains a speed of 20 m/sec

Let the mass of the truck is m

At the top of the hill potential energy is mgh and kinetic energy is \frac{1}{2}mv^2

So total energy at the top of the hill =mgh+0=mgh

At the bottom of the hill kinetic energy is equal to \frac{1}{2}mv^2 and potential energy will be 0

So total energy at the bottom of the hill is equal to 0+\frac{1}{2}mv^2

Form energy conservation mgh=\frac{1}{2}mv^2

v=\sqrt{2gh}, for v = 20 m/sec

20=\sqrt{2\times 9.8\times h}

Squaring both side

19.6h=400

h = 20.408 m

Now if velocity is 0 m/sec

40=\sqrt{2gh}

19.6h=1600

h = 81.63 m

So we can see that to achieve the velocity of 40 m/sec height will become 4 times

You might be interested in
A large, 34.0 kg bell is hung from a wooden beam so it can swing back and forth with negligible friction. The bell's center of m
Lorico [155]

Answer:

length L of the clapper rod for the bell to ring silently = 0.756m

Explanation:

We are given;

Mass of Bell;m_b = 34 kg

Distance of centre of mass from pivot;d = 0.7m

The bells moment of inertia about an axis at the pivot;I = 18 kg.m²

Mass of clapper;m_c = 1.8 kg

Length of slender rod is L

Now, the formula for period of physical pendulum having small amplitude is given as;

T_b = 2π√(I/mgd)

Where;

I is moment of inertia

m is mass

g is acceleration due to gravity = 9.8 m/s²

d is distance from rotation axis to centre of gravity

Plugging in the relevant values and using mass of bell, we have;

T_b = 2π√(18/(34*9.81*0.7)

T_b = 2π√(18/(34*9.81*0.7)

T_b = 1.745 s

Now, the formula for period for a simple pendulum which is essentially what the clapper rod is would be;

T_c = 2π√(L/g)

Now, we want to find length of clapper L.

Thus, let's make it the subject;

L = g(T_c/2π)²

Now, we are told that for the bell to ring silently, T_b = T_c.

Thus, T_c = 1.745 s.

So,

L = 9.8(1.745/2π)²

L = 0.756m

7 0
3 years ago
Which of the following statements is true regarding the use of refrigerants?
Damm [24]
B.

Refrigerants should be handled using approved equipment only.
5 0
3 years ago
Read 2 more answers
Convert the following to gram. a,250 kg b373 mg c,10 quanital,15 ton​
rusak2 [61]

Explanation:

250 KG = 250000 Grams

373 MG = 0.373 Grams

10 Quintals = 1000000 Grams

15 Ton = 15000000 Grams

Please Follow and inbox me

4 0
2 years ago
A marble resting near the edge of .90 m high table is given an initial horizontal speed of 1.24 m/s. What will be it’s horizonta
Maru [420]

Answer:

0.53 m

Explanation:

First of all, we have to consider the vertical motion of the ball, in order to find the time it takes for the marble to reach the ground. The initial height is h=0.90 m, the initial vertical velocity is zero, while the acceleration is g=-9.81 m/s^2, so the vertical position at time t is given by

y(t)=h-\frac{1}{2}gt^2

By demanding y(t)=0, we find the time t at which the ball reaches the ground:

0=h-\frac{1}{2}gt^2

t=\sqrt{\frac{2h}{g}}=\sqrt{\frac{2(0.9 m)}{9.81 m/s^2}}=0.43 s

Now we can find the horizontal range of the marble: we know the initial horizontal speed (v=1.24 m/s), we know the total time of the motion (t=0.43 s), and since the horizontal speed is constant, the total distance traveled on the horizontal direction is

x=vt=(1.24 m/s)(0.43 s)=0.53 m

8 0
3 years ago
9. A sports car travels on a straight road at 22.0 km/h and increases its speed to 57.0 km/h in
Varvara68 [4.7K]

Answer:

4.4 M/s

Explanation:

6 0
3 years ago
Other questions:
  • What generates the magnetic field that surrounds a wire carrying an electric current?
    11·1 answer
  • E. A racing car has a mass of 710kg. It starts from rest and travels 120m in
    5·1 answer
  • Two airplanes leave an airport at the same time. The velocity of the first airplane is 740 m/h at a heading of 25.3◦. The veloci
    7·1 answer
  • What is the study of atoms​
    6·2 answers
  • Explain the method to measure the external diameter of a sphere
    11·1 answer
  • An artificial satellite orbits Earth at a speed of 7800 m/s and a height of 200 km above Earth’s surface. The satellite experien
    7·1 answer
  • Which method is responsible for the transfer of heat in the atmosphere ?
    6·1 answer
  • Kara is pushing a shopping cart to the right. The gravitational force is acting ________.
    7·1 answer
  • Can someone help answer question 8?
    14·2 answers
  • A flat, square surface with side length 4.35 cm is in the xy-plane at z=0.
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!