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
Bess [88]
2 years ago
12

A child is stationary on a swing.(a)The child is given a push by his brother to start him swinging.His brother applies a steady

force of 84 N over a distance of 0.25 m.(i) Calculate the work done by this force.(2)..............................................................................................................................................(ii) State how much energy is transferred by this force.(1)..............................................................................................................................................(iii) After several more pushes, the child has a kinetic energy of 71 J.The mass of the child is 27 kg.Show that the velocity of the child at this point is about 2.3 m/s.(2)(iv) Which one of these quantities changes in both size and direction while he is swinging?Put a cross ( ) in the box next to your answer.(1)Ahis gravitational potential energyBhis momentumCthe force of gravity acting on himDhis kinetic energy
Physics
1 answer:
lys-0071 [83]2 years ago
6 0

Answer:

Work done = Fs

Explanation:

(i) W = Fxs

= 84N x0.25m

= 21 Joules

(ii) Ek = 1/2mv^2

71 = 1/2×27×v^2

71×2/27 = v^2

v = 23m/s

You might be interested in
What molecule determines the characteristics a child will inherit from its parents?
Korvikt [17]

Answer:

A molecule called DNA (deoxyribonucleic acid) is passed from adult organisms to their offspring during reproduction. This molecule containsthe instructions for an organism to develop, grow, survive and reproduce.

8 0
2 years ago
Our body contains ______________ potential energy from food we have eaten.
Alisiya [41]

Answer: Our body contains chemical potential energy from food we have eaten.

This chemical potential energy is transformed into the kinetic energy of our hands and arms as we rub our hands together.

As our hands move past each other and rub against each other, friction allows the kinetic energy to be transformed into thermal energy on the surface of our hands.

Explanation:

It is true that our food contains chemical bonds and these bonds have potential energy stored. So, when we eat food then our body acquires chemical potential energy.

When we rub our hands and arms then they form kinetic energy as atoms present within the skin of our hands come into motion. This rubbing of hands leads to the formation of heat which means thermal energy is being generated.

Thus, we can conclude that our body contains chemical potential energy from food we have eaten.

This chemical potential energy is transformed into the kinetic energy of our hands and arms as we rub our hands together.

As our hands move past each other and rub against each other, friction allows the kinetic energy to be transformed into thermal energy on the surface of our hands.

5 0
2 years ago
If you walk 3 kilometers in 30 minutes , what is the average speed in kilometers per hour?
Pepsi [2]

Answer:

6 km/h

Explanation:

V avg = ∆x/∆t = 3km / 30 min ×(60min/1h) = 3 km× 2 /h = 6 km/h

4 0
2 years ago
Which factor is most important in determining climate?
alisha [4.7K]
Temperature. The other three dont have anything to do with determining climate

8 0
3 years ago
Read 2 more answers
The temperature at one of the Viking sites on Mars was found to vary daily from -90.OF to -5.0 C. Convert these temperatures to
kykrilka [37]

Answer:

I don't know about this, this is which class question

6 0
2 years ago
Other questions:
  • A soccer player kicks a ball down the field. It rolls to a stop just before the goal. Which statement accurately describes the m
    15·1 answer
  • Why can light microscopes produce images in their natural color
    6·1 answer
  • Please help answer #14!!!!!!!
    8·1 answer
  • Is the classification for an instrument that produces sound whne a string or strings stretched between two points is plucked?
    13·1 answer
  • A person travels by car from one city to another with different constant speeds between pairs of cities. She drives for 30.0 min
    5·1 answer
  • students make a small elevator machine with 5 kg and 10 kg masses on either side how fast will the masses accelerate once they a
    8·1 answer
  • What happens when someone is walking across the carpeted room then touches a metal door knob
    11·1 answer
  • A car travels 85 km in the first half hour of a trip. The car continues to travel for 2 more hours and travels 200 km. What was
    13·1 answer
  • Which is NOT a way to stay safe from static electricity?
    10·2 answers
  • Sorry that i ask for too much but I'm horrible at this ⭐-_-
    6·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!