1. What is the weight (in Newtons) of a 14.0 kg pumpkin on Earth? 2. A Bullet (m
ID: 2144328 • Letter: 1
Question
1. What is the weight (in Newtons) of a 14.0 kg pumpkin on Earth?
2. A Bullet (mass = 0.01kg) is shot into a 3.0 kg block of wood that is initially at rest. Immediately after the bullet becomes buried in the block, they slide forward (together) at a speed of 2.25 m/s. How fast (in m/s) was the bullet moving when it struck the block?
3.Two students push a desk across a frictionless floor. One student pushes with a force of 75.0N. The desk has a mass of 100.0kg and accelerates at 2.00 m/s(squared). With what force (in N) did the student push?
4.a collision between two objects in which they remain joined together after the collision is called?
5. In a figure skating event, a 65.0 kg male skater pushes a 45.0 kg female skater, causing her to accelerate at +2.00 m/s(squared). What is the male skaters acceleration?
6. A ball of mass m is dropped from the window of the fourth floor of an office building, subsequently hitting the sidewalk below at speed v. From what floor should the ball be dropped to double that impact? The 6th, 8th, 10th, 12th, 16th floor?
7. A 1250 kg car is traveling 90.0 km/h. If the car's brakes are able to apply a total of 10,500N of force to the car while it stops, what distance (in meters) will the car travel before it stops?
8. If a box slides down an inclined ramp at a constant velocity, the ramp must be frictionless. True/False, or not enough information?
9. A baseball (mass = 0.144 kg) is traveling to the right at 30.0 m/s when it is struck by a bat. The bat is moving to the left and applies a large force to the ball in 0.001 seconds. The velocity of the ball is -67.0 m/s to the left after contact with the bat. How many Newtons of force was applied to the bat?
10. A skier pushes off the top of an icy, frictionless hill with an initial speed of 4.00 m/s. How fast (in m/s) will she be traveling after descending 10.0 m in elevation?
11. A 50.0 kg crate is lifted to the top of a warehouse 21.0 meters high in 12.0. How many Joules of work are done on the crate?
12. A ship is driven through the water by three propellers, each providing a force of 12,500 Newtons. The drag of the water on the ship's hull creates a frictional force of 8,550 Newtons. If the ship is able to accelerate at 1.55 m/s(squared), whaat is its mass (in kilograms)?
13. A net force acting on a body can cause which of the following?
A, an acceleration B, A change in Velocity C, A change in momentum D, All of these E, A and B
14. A person pushes a 10.0 kg box from rest and accelerates it to a speed of 4.00 m/s with a constant force. If the box is pushed for a time of 2.50 seconds, what is the force (in Newtons) exerted by the person.
15. Water flows over a 18.0 meter high waterfall at the rate of 5400kg each second. If a generator is placed at the bottom of the waterfall, how many Watts of power could it produce, assuming it is 100% effiecient?
16. A ball is dropped from the roof of a building. Compare its kinetic energy to its potential energy/
A, KE and PE decrease B, KE and PE remain constant C, KE and PE Increase D, KE decreases PE increases E, KE increases PE decreases
17. An object with no external unbalanced forces acting on it is
A, at rest B, accelerating C, Moving at constant velocity D, either A or C E, either B or C
18. A brick hits a glass window. The brick breaks the glass. Which of the following is true?
glass force is greater than the brick force, brick force is greater than glass force, both forces are equal, none?
19. A 1250 kg automobile is traveling at 90.0 km/h. How many Joules of work must be done by its brakes in order to bring the car to rest?
20. When a bullet is fired from a rifle, the bullet travels forward out of the barrel and the rifle recoild backward. Which object has a greater momentum?
21. Impulse is?
22. Suppose a moving baseball and moving golf ball have the same momentum. Which has greater kinetic energy? (baseball has about 3 times more mass than a golfball)
23. A 50.0 kg crate is lifted to the top of a warehouse 21.0 meters high in 12.0 seconds. What is the power of the motor (in Watts) that lifted the crate?
24. The work done by a constant force on an object which remains at rest is... positive, negative, or zero?
Explanation / Answer
1) W = m g = 14*9.81 =137.34 N
2) conservation of momentum
0.01*v = (3+0.01)*2.25
v = 677.25 m/s
3) sum of F = ma
75 + F = 100*2
F = 125 N
4) inelastic collision
5) F 1 = F2
65*a = 45*2
a = 90/65= 1.38 m/s^2
6) v^2 = v0^2 + 2 a y
v = sqrt( 2 a y)
so to double v need to 4 times y
so 4*4 = 16th floor
7)
90 km/hr = 25 m/s
a = F/m = 10500/1250
v^2 = v0^2 + 2 a x
x = v^2/2a = 25^2/(2*10500/1250)=37.2 m/s
8)
false since something has to oppose gravity
9) F = dp/dt = 0.144* (67+30)/0.001=13968 N
10) conservation of energy
1/2 mv^2 + mg h = 1/2 mv^2
0.5*4^2 + 9.81*10 = 0.5*v^2
v=14.57 m/s
11) W = m g h = 50*9.81*21=
10300 J
12) 3*12500 - 8550 = 1.55*m
m=18677 kg
13) D all of these
14) v = v0 + at
a = v/t = 4/2.5
F = ma = 10*4/2.5= 16 N
15) W = dm/dt g h = 5400*9.81*18= 953532
16) D Ke decrease PE incr4eases
17) D) either A or C
18) newtons third law
both forces are equal,
19)
90 km/hr = 25 m/s
W = dKE = 0.5*1250*25^2= 390625J
20) conservation of momentum
so they are equal
21) impulse is change in momentum
22) KE = p^2/2m
so if same momentum bigger mass has smaller kinetic energy
so golf ball
23) P = m gh/t= 50*21*9.81/12= 858 W
24) work = dKE = 0
so zer0
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.