1) A horse pulls on a crate with a 1,000 N force, causing it to move at constant
ID: 1521095 • Letter: 1
Question
1) A horse pulls on a crate with a 1,000 N force, causing it to move at constant velocity. What is the acceleration of the cart? A 44-kg child steps onto a scale. What is the magnitude of the force that the scale exerts on the child?
2) What is resonance? Discuss examples of how resonance can be useful and harmful.
3) Suppose in a restaurant your coffee is served about 5 or 10 minutes before you are ready for it. If you want the coffee to be as hot as possible when you drink it, should you pour in the room temperature cream right away or when you are ready to drink the coffee?
4) Advertisements for a toy ball once stated that it would rebound to a height greater than the height from which it was dropped. Is this possible? Why or why not?
Explanation / Answer
1)If the cart moving with constant velocity the acceleration will be zero because acceleration obtained from the change in the velocity with the time
so the acceleration of the cart is zero.
2) when the child steps onto a scale it exerts normal force on the child and this force should be equal to the weight of the child so,
the force that the scale exerts on the child (F) =mg
here m is the mass of the child =44 kg and g =acceleration due to gravity =9.81 m/s2
on substituting we get F =(44 kg)(9.81 m/s2) =431.64 N
the force that the scale exerts on the child is 431.64 N
2) Resonance is defined as an object free to vibrate tends to do so at a specific rate called the object's natural, or resonant, frequency. (This frequency depends on the size, shape, and composition of the object.) Such an object will vibrate strongly when it is subjected to vibrations or regular impulses at a frequency equal to or very close to its natural frequency. This phenomenon is called resonance.In resonance the two object vibrate with maximum frequency
The best use of resonance is in the music instruments. Music is all about resonance. When a string is plucked or otherwise stimulated it will sound at its resonant frequency. That is why piano or harp strings are all different lengths
And resonance should be avoided in some cases for example during, soldiers marching in formation had to break step when they crossed a bridge because regular, rhythmic stimulus to the bridge could cause it to resonate or vibrate it and cause it to collapse
3) To keep your coffee hot for as long as possible, add cream right away. It turns out that coffee with cream added actually cools about 20% more slowly than plain black coffee, so it is best to add the cream immediately.The coffee with cream cools more slowly because ,The fat in the cream is better at retaining heat and floats rather well, locking the heat in, distributing heat more evenly around in the liquid giving it a much slower evaporation
thats why the cream with coffee retaining temperature and keep the coffee hot.
4)It is not possible because , in this case the energy wouldn't be conserved. When the ball dropped from a height ,it contains potential energy. When the ball hit the ground some of these energy converted and lost in the form of heat and sound and remaining energy retained by ball used in the rebound of it, so less energy caused to rise less height after the rebound.
Therefore the ball would rebound to a height less than the height from which it was dropped
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.