Mechanics | Relativity Answers

A motorist traveling at 11 m/s encounters a deer in the road 45 m ahead.
If the maximum acceleration the vehicle’s brakes are capable of is −7 m/s
2, what is themaximum reaction time of the motorist that will allow her or him to avoid hitting the deer?
Answer in units of s.

A stone with a mass of 0.450 kg is dropped from the edge of a cliff. When the stone strikes the ground, the internal energy of the stone and ground increase by 1770 J. Ifthe stone is initially at rest when it is dropped, how high above the ground is the cliff?

A car driver travelling at 90km/h, notices that he is heading directly to a cliff when he is 20m away from the edge. He applies the brakes and experiences a backward acceleration of 8.0 m/s2, but it's not enough. The car goes off the cliff, if the cliff is 12m high, how far is the car traveling horizontally until it lands?

When comparing Einstein's mass energy equivalence E=mc^2 with potential energy in linear movement ( one diamention or in space)
mc^2=mgh
in space g=acc and h=S(distance)
c^2=aS
to find the maxi distance that can be travelled by a mass m with acc a is S
S=c^2/a
when acc = c/5
S=5c
Thus when the object moves with a acc of c/5 then the maximum distance travelled by the body without change of mass into energy is 15x10^5 kms only.
I have a doubt whether this is correct or not.

A swimmer sees an object that falls on the sea. He hears the sound of impact twice: once by the ear that is below the water surface and the other time by the ear that is in the air, 1 second later. At what distance from the observer did the impact took place??

An air bubble rises from bottom of lake to the surface. If its radius increases by 200% and atmospheric pressure is equal to water coloumn of height H, then depth of lake is:

1) 21H

2) 8H

3) 9H

4) 26H

A mass is attatched to a spring, displaced and then released from rest with an angular velocity of 0.5 rad/s. Determine the time hen the kinetic energy and potential energy are first equal

Block A of mass4.0 kg is on a horizontal frictionless tabletop and is placed against a spring of negligible mass and spring constant 650 Nm. The other end of the spring is attached to a wall. The block is pushed toward the wall until the spring has been compressed a distance x, as shown above. Block A is released, then strikes and sticks to Block B at the edge of the table. The blocks then fall to the ground following the trajectory shown, falling 0.80 m vertically to the floor. Air resistance is negligible.

5. The spring has 3.25 J of elastic potential energy when it is compressed distance x. Determine the distance x.

6. Determine the velocity of Block A on the table when it leaves contact with the spring.

7. Determine the velocity of the stuck together blocks immediately following the collision.

8. What is the total kinetic energy of the blocks just before they hit the floor?

Please show work if possible! Thank you!

A man strikes a nail into a wooden block with an average force of 200N.if he continues to strike the nail with that force estimate how much heat energy Will be generated by the time the nail penetrates a depth of 0.05m

A racing car is travelling along a straight track at a constant velocity of 40 m/s. A fixed TV camera is recording the event as shown in figure. In order to keep the car in view, in the position shown, the angular velocity of camera should be