Answer:
speed of car = 95 km/h
speed of truck = 75 km/h
relative speed of car with respect to truck = 95 - 75 = 20 km/h
now we will convert it into m/s
now time to cross the truck will be given as
time = 19.8 s
so it will take 19.8 s to cross the truck
Explanation:
Every magnet has at least one “North” and one “South” pole where its magnetic forces leave the magnet and enter its surroundings. It is commonly thought that the magnetic forces leave one pole and enter the other pole. Therefore, The magnetic forces are <span>concentrating the forces between those poles and making the attraction/repulsion stronger. Hope this helps! :)
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25 volts
Explanation:
Use Ohm's law to find the potential drop:
V = IR
= (0.5 A)(50 ohms)
= 25 volts
One of the major effects of heat transfer is temperature change: heating increases the temperature while cooling decreases it. We assume that there is no phase change and that no work is done on or by the system. Experiments show that the transferred heat depends on three factors—the change in temperature, the mass of the system, and the substance and phase of the substance.
Figure a shows a copper-colored cylinder of mass m and temperature change delta T. The heat Q, shown as a wavy rightward horizontal arrow, is transferred to the cylinder from the left. To the right of this image is a similar image, except that the heat transferred Q prime is twice the heat Q. The temperature change of this second cylinder, which is also labeled m, is two delta T. This cylinder is surrounded by small black wavy lines radiating outward. Figure b shows the same two cylinders as in Figure a. The left cylinder is labeled m and delta T and has a wavy heat arrow pointing at it from the left that is labeled Q. The right cylinder is labeled two m and delta T and has a wavy heat arrow pointing to it from the left labeled Q prime equals two Q. Figure c shows the same copper cylinder of mass m and with temperature change delta T, with heat Q being transferred to it. To the right of this cylinder, Q prime equals ten point eight times Q is being transferred to another cylinder filled with water whose mass and change in temperature are the same as that of the copper cylinder.
Answer:
(a) F = 239.575 N (b) t = 0.00649s or 6.49 ms
Explanation:
(a) By law of energy conservation, the bullet kinetic energy will be transferred to work done on stopping it from moving.
Formula for Kinetic Energy 
where m is bullet mass, v is the velocity
Formula for work 
where F is the average force and S is the distance travelled.
Substitute m = 4.2 g = 0.0042 kg, v = 370 m/s and S = 1.2 (m)
(b) If the force is constant, since the mass is constant and F = ma according to Newton's 2nd law, the acceleration on bullet is also constant
We also have 
At the time the bullet is coming to rest, 
Therefore, 
