Question
1. There is a 10 kg textbook resting on a table (1m) above the ground, you want to raise the book 0.8m above that.
a. What is the change in potential energy to do so?
(I did w= 1.8*98?)
b. If you hold the book there (0.8 above the table) for 10m what is the work being done?
(I did w= 1.8*98*10?)
2. A puck is sliding on ice at velocity v, if another puck is added and sticks to the first puck what is that combined velocity?
(I got 2v?)
3. A plane is flying at v=300 km/h there is a wind from southwest at v= 60km/h. Find ground velocity of the plane.
(I did sqr ((300)^2+(60)^2))
4. A projectile is launched at v= 15m/s at an angle 60 above the horizontal.
a. What is the vertical velocity when it lands?
b. What is the acceleration halfway when projectile reaches max height?
a. What is the change in potential energy to do so?
(I did w= 1.8*98?)
b. If you hold the book there (0.8 above the table) for 10m what is the work being done?
(I did w= 1.8*98*10?)
2. A puck is sliding on ice at velocity v, if another puck is added and sticks to the first puck what is that combined velocity?
(I got 2v?)
3. A plane is flying at v=300 km/h there is a wind from southwest at v= 60km/h. Find ground velocity of the plane.
(I did sqr ((300)^2+(60)^2))
4. A projectile is launched at v= 15m/s at an angle 60 above the horizontal.
a. What is the vertical velocity when it lands?
b. What is the acceleration halfway when projectile reaches max height?
Answers
Henry2,
1a.
PE change = PE2 - PE1 = Mgh2 - Mgh1 = (10*9.8*1.8) - (10*9.8*1.0) =
1b. W = F*d =(M*g) * d = (98) * 0.8 Joules.
3. What is the direction of the plane?
4. Vo = 15m/s[60o].
a. Xo = 15*Cos60 = 7.5 m/s = Hor. component of initial velocity.
Yo = 15*sin60 = 13.0m/s = Vertical component of initial velocity.
Y^2 = Yo^2 + 2g*h = 0.
13^2 + (-19.6)h = 0 ,
h = 8.62 m. = Max. ht.
Y^2 = Vo^2 + 2g*h = 0 + 19.6*8.62 = 169,
Y = 13m/s = Vertical velocity when it lands.
b. a = g = -9.8 m/s^2.
PE change = PE2 - PE1 = Mgh2 - Mgh1 = (10*9.8*1.8) - (10*9.8*1.0) =
1b. W = F*d =(M*g) * d = (98) * 0.8 Joules.
3. What is the direction of the plane?
4. Vo = 15m/s[60o].
a. Xo = 15*Cos60 = 7.5 m/s = Hor. component of initial velocity.
Yo = 15*sin60 = 13.0m/s = Vertical component of initial velocity.
Y^2 = Yo^2 + 2g*h = 0.
13^2 + (-19.6)h = 0 ,
h = 8.62 m. = Max. ht.
Y^2 = Vo^2 + 2g*h = 0 + 19.6*8.62 = 169,
Y = 13m/s = Vertical velocity when it lands.
b. a = g = -9.8 m/s^2.